Interventions in Glasshouse for a Botanical Exhibition Space

DIRECTED STUDIES (V/I) INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE SUBMITTED BY Emil Shrestha 66011 | B.Arch. 066, V/I March 2014 Department of Architecture Kathmandu Engineering College Kalimati, Kathmandu INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Abstracts The study and report is prepared as a partial fulfillment for the subject Directed Studies and Seminar, as stipulated in the syllabus of ninth semester (V year, first part) of Bachelor degree in the course of Architecture, by Institute of Engineering, Tribhuwan University. The report is prepared on the basis of the study done on the greenhouses and its corresponding subjects to improvise it as a well-functioning botanical exhibition space. The study is done on the basis of the secondary data for literature review and case study on the Eden Project. Whereas, the case study on the National Botanical Garden is based on the field visits and interviews. The literature study is based on the greenhouses and its corresponding features, services and amenities. As greenhouses deal with plants, a brief plants study is done for the purpose of creating the required environment for the plants. Lastly, considerations for exhibitions are studied to facilitate the greenhouse with proper planning and design as an exhibition space. To understand the use of greenhouse more as an exhibition space, the case study of the Eden Project based in UK is done. The advance engineering and material technologies used in the project is a good example for a greenhouse as a large biome used for exhibition purpose. Whereas, the study on the glasshouses of the National Botanical Garden depicts the simplicity of the structures as a botanical exhibition space and points out the places for improvements. Lastly, the researched information are compared and analysed, which have helped to plot the suggestive recommendations for the necessary interventions in greenhouses to act it as a botanical exhibition space. The study and the report is more specific on a subject. I hope this material can be helpful in the corresponding field of practice related to plants conservation and display. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 1 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Acknowledgements This project is a part of my academic work as a requirement in the syllabus of Bachelor Degree in Architecture for the subject, Directed Studies and Seminar. I would like to express my gratitude to my teachers Ar. Shailita Manandhar Joshi, Ar Kailash Shrestha, Ar. Moon Singh Dongol and Ar. Sweta Shrestha of the Department of Architecture, Kathmandu Engineering College. They have guided and supervised me during the study phase and in the preparation of this report. Likewise, I would also like to thank botanists, Mr. Deepak Lamichhane and Mr. Dinesh Baral of National Botanical Garden, Godawari for permitting the study of the relevant subjects inside the institution and for helping me with the study phase. Also, I am thankful for all those who have helped me during the study on the corresponding subjects and in the preparation of this report. I hope the study will be extremely beneficial for the forthcoming thesis projects and other related fields. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 2 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Abstracts ............................................................................................................................. 1 Acknowledgements............................................................................................................. 2 List of Figures ..................................................................................................................... 6 Table of Contents 1. Introduction .................................................................................................................. 7 1.1. Background ..............................................................................................................7 1.2. Problem statement ...................................................................................................7 1.3. Objectives of the study .............................................................................................7 1.4. Rationale of the study...............................................................................................8 1.5. Scope and focus ......................................................................................................8 1.6. Methodology.............................................................................................................8 LITERATURE STUDY 2. Greenhouses ................................................................................................................ 9 2.1. Introduction ..............................................................................................................9 2.2. History .................................................................................................................... 10 2.3. Working principles .................................................................................................. 11 2.4. General design considerations ............................................................................... 11 2.4.1. Siting ............................................................................................................... 11 2.4.2. Height of greenhouse structure ....................................................................... 12 2.4.3. Framework ...................................................................................................... 12 2.4.4. Coverings ........................................................................................................ 13 2.4.5. Ground cover .................................................................................................. 15 2.4.6. Adjacent Facilities ........................................................................................... 15 2.5. Types of Greenhouse ............................................................................................. 15 2.5.1. Shape and design ........................................................................................... 15 2.5.2. Other types of structures ................................................................................. 17 2.6. Utilities and services............................................................................................... 18 2.6.1. Greenhouse heating ........................................................................................ 19 2.6.2. Greenhouse cooling ........................................................................................ 20 2.6.3. Greenhouse ventilation ................................................................................... 21 2.6.4. Greenhouse Plant growing .............................................................................. 22 2.6.5. Greenhouse irrigation and nutrition ................................................................. 24 2.6.6. Lightings.......................................................................................................... 25 2.7. Other features ........................................................................................................ 26 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 3 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 3. Plants Study ............................................................................................................... 28 3.1. Introduction ............................................................................................................ 28 3.2. Plant Taxonomy ..................................................................................................... 28 3.2.1. Identification, classification and description ..................................................... 28 3.2.2. Binomial nomenclature .................................................................................... 29 3.3. Vegetative and reproductive characteristics ........................................................... 29 3.4. Plants propagation ................................................................................................. 29 3.4.1. Sexual propagation (seed) .............................................................................. 29 3.4.2. Asexual propagation........................................................................................ 30 3.5. 4. Ecological distribution of plants .............................................................................. 30 3.5.1. Tropical rainforests .......................................................................................... 31 3.5.2. Tundra............................................................................................................. 32 3.5.3. Taiga (Coniferous) .......................................................................................... 33 3.5.4. Temperate deciduous forest ............................................................................ 34 3.5.5. Mediterranean scrub ....................................................................................... 34 3.5.6. Temperate grasslands..................................................................................... 35 3.5.7. Desert scrub .................................................................................................... 35 3.5.8. Tropical Savannas .......................................................................................... 36 Exhibitions Considerations ....................................................................................... 38 4.1. Introduction ............................................................................................................ 38 4.2. General design considerations ............................................................................... 38 4.2.1. Planning and circulation .................................................................................. 38 4.2.2. Entrance.......................................................................................................... 39 4.2.3. Display ............................................................................................................ 39 4.2.4. Lighting ........................................................................................................... 40 CASE STUDY 5. The Eden Project ........................................................................................................ 41 5.1. Introduction ............................................................................................................ 41 5.2. The biomes ............................................................................................................ 41 5.3. Siting ...................................................................................................................... 42 5.4. Structures............................................................................................................... 42 5.5. Coverings ............................................................................................................... 43 5.6. Other features ........................................................................................................ 43 5.6.1. Soil Nourishment ............................................................................................. 43 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 4 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 6. 5.6.2. Water management and irrigation ................................................................... 44 5.6.3. Circulation and viewing facilities ...................................................................... 44 National Botanical Garden, Godavari ....................................................................... 45 6.1. Introduction ............................................................................................................ 45 6.2. The Tropical House ................................................................................................ 45 6.2.1. Planning and Circulation ................................................................................. 45 6.2.2. Structure and coverings .................................................................................. 46 6.2.3. Utilities ............................................................................................................ 46 6.3. 7. 8. 9. Other glasshouses ................................................................................................. 47 Comparative Analysis ................................................................................................ 48 7.1. Siting ...................................................................................................................... 48 7.2. Structures and material technologies ..................................................................... 48 7.3. Utilities and services............................................................................................... 48 7.4. Exhibition considerations ........................................................................................ 49 Recommendations ..................................................................................................... 50 8.1. Purpose.................................................................................................................. 50 8.2. Siting ...................................................................................................................... 50 8.3. Structures and material technologies ..................................................................... 50 8.4. Utilities and services............................................................................................... 50 8.5. Planning and circulations........................................................................................ 51 Bibliography ............................................................................................................... 52 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 5 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE List of Figures Figure 2-1: Biomes of The Eden Project ................................................................................ 9 Figure 2-2: Working principles of greenhouses .................................................................... 11 Figure 2-3: Double polycarbonate sheets ............................................................................ 13 Figure 2-4: Structural types of Greenhouse ......................................................................... 16 Figure 2-5: Example of a geodesic dome ............................................................................ 17 Figure 2-6: General utilities and services in greenhouse ..................................................... 18 Figure 2-7: General heat loss in greenhouse ....................................................................... 19 Figure 2-8: Normal air heater used for greenhouse ............................................................. 20 Figure 2-9: Relationship between light and photosynthesis process .................................... 25 Figure 2-10: Example of a well-lit greenhouse ..................................................................... 26 Figure 2-11: Example of a greenhouse environment monitoring device ............................... 26 Figure 3-1: Plants vegetative characteristics ....................................................................... 29 Figure 3-2: Ecological Distribution of terrestrial biomes ....................................................... 30 Figure 3-3: Climatic data in the various terrestrial biomes ................................................... 31 Figure 3-4: Tropical rainforest.............................................................................................. 31 Figure 3-5: Plant layers in the rainforest .............................................................................. 32 Figure 3-6: Tundra vegetation ............................................................................................. 32 Figure 3-7: Taiga vegetation ................................................................................................ 33 Figure 3-8: Temperate deciduous forest .............................................................................. 34 Figure 3-9: Mediterranean vegetation .................................................................................. 34 Figure 3-10: Temperate grasslands vegetation.................................................................... 35 Figure 3-11: Warm desert vegetation .................................................................................. 36 Figure 3-12: Tropical Savannas vegetation ......................................................................... 36 Figure 4-1: Circulation diagram ........................................................................................... 38 Figure 4-2: Field of vision: height, distance.......................................................................... 39 Figure 5-1: Aerial view of the Eden Project .......................................................................... 41 Figure 5-2: Schematic Master plan ...................................................................................... 42 Figure 5-3: Steel tubes are used in geodesic dome ............................................................. 43 Figure 5-4: ETFE foils being installed in between the steel frames ...................................... 43 Figure 5-5: The ETFE foil covering with louvers vents framed by aluminum profiles ............ 43 Figure 5-6: Narrow pathways with sprinklers attached ......................................................... 44 Figure 5-7: Misting system used for irrigation ...................................................................... 44 Figure 5-8: Wide pathways inside ........................................................................................ 44 Figure 5-9: Overhead steel platform providing view of the inside ......................................... 44 Figure 6-1: The Tropical House from south ......................................................................... 45 Figure 6-2: : Inside the tropical house.................................................................................. 45 Figure 6-3: Plan ................................................................................................................... 45 Figure 6-4: Use of steel portal frames .................................................................................. 46 Figure 6-5: Ponds with pebbles pavements ......................................................................... 46 Figure 6-6: Elevations.......................................................................................................... 46 Figure 6-7: Sprinklers installed for irrigation ......................................................................... 46 Figure 6-8: Typical sections of the glasshouses .................................................................. 47 Figure 6-9: Wooden post supported cacti greenhouses ...................................................... 47 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 6 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 1. Introduction 1.1. Background Glasshouses have been used to grow plants by providing them favorable environment. These structures are used for various researches on the botany and are also being widely used for the commercial purposes. However, in the botanical garden these structures are one of the main architectural attractions for the visitors and the researchers. Initially, greenhouses were built in Italy to house the exotic plants that explorers brought back from the tropics. ‗Active‘ greenhouses, in which it is possible for the temperature to be increased or decreased manually, appeared much later. Some of these early attempts required enormous amounts of work to close up at night or to winterize. There were serious problems with providing adequate and balanced heat in these early greenhouses. Originally only on the estates of the rich, the growth of the science of botany caused greenhouses to spread to the universities. Experimentation with the design of greenhouses continued during the 17th century in Europe, as technology produced better glass and construction techniques improved. In present day, various greenhouses have been constructed with different technologies and also for various purposes. With the advancement of the technologies the size and the features of the green houses also have exceeded the previous ones. Now, the green houses are designed more as biomes or biospheres with the intention to preserve the plant species as well as to display the species. These glasshouses are incorporated with various environmental control units to maintain favorable environment for the plant beings. While developing the greenhouses into exhibition spaces special cares are to be taken to maintain the environment inside. For a well-functioning of a greenhouse various features are to be considered. Transforming a normal greenhouse into a botanical exhibition space is a challenge. Observing facilities and services are to be catered for the visitors along with a special care not to disturb the micro climate and environment for the growth of the plant species. 1.2. Problem statement Necessary interventions are to be taken to improvise the glass house as an exhibition space for the display of the botanical entities. 1.3. Objectives of the study The objectives of the study are as follows: • To understand the essential features of a well-functioning greenhouses. • To study the utilities and services for the functioning of a greenhouse. • To understand the plant characteristics to house in the greenhouse. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 7 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 1.4. Rationale of the study Glasshouse is an essential architectural component in a botanical garden. It is used as a conservatory to preserve the plant species by creating favorable environment. Also, it provides opportunities for the researchers to study on the plant species and their characteristics. In addition to this, glass houses receive number of visitors to know the plant species and for their leisure too. Glasshouses are well-equipped with various control units and other utilities to favor the growth of the plant species. To host the conservatory for the exhibit, the designing and planning of the necessary services and utilities for the species and for the well guidance of the visitors are necessary. Hence, this dissertation will study the interventions in the glasshouse to host the visitors and researchers in such a way that the enclosed ecosystem is not disturbed. 1.5. Scope and focus The study includes the following heads: • Glasshouse and its working principles • Services and utilities to maintain the indoor environment of the glasshouse • Materials and technologies in construction of the glasshouse • Features to be considered to make the glasshouse as an exhibition space of plants. • Services and provisions for the visitors inside the glasshouse. • General study of the plant species and their environmental characteristics This study does not include: • The detail study of the individual plant species to be featured in the glasshouse. • The cost detail of the construction of the glasshouse. • The technical specifications for the construction details of the greenhouse. 1.6. Methodology The study is primarily based on the secondary data available in the internet. International case studies are also based on the online study of the institutions. Whereas, national case studies are prepared on the basis of the field visits. Also, some interviews were taken on the related subject matters. The methods of study can be briefed as follows: EMIL SHRESTHA; 66011, B. Arch. 066, V/I 8 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 2. Greenhouses Introduction 2.1. Greenhouses are structures where plants are grown in a maintained favorable environment. These structures range in size from small sheds to industrial-sized buildings. These structures are made up of glazing materials as skin and are equipped with various installations like heating, cooling, lightings, irrigation etc. to maintain a desired micro climate required for the plants growth. Where the covering material is glass, the structure may be referred to as a 'glasshouse'. A 'greenhouse' or 'polyhouse' refers to the use of plastic films or sheeting. When the enclosing material is woven or otherwise constructed to allow sunlight, moisture and air to pass through the gaps, the structure is known as a 'shade house' or 'screen house'.1 Generally, greenhouses are used as a small gardening unit in residences and gardens and known as conservatories. According to Wikipedia ―A conservatory is a room having glass roof and walls, typically attached to a house on only one side, used as a greenhouse or a sunroom.‖2 Also, the greenhouses are scaled large enough for industrial productions of food and plants. In educational institutes greenhouses are used for the conservatory, repository and research of various plant species. Recently, large greenhouses are constructed to house micro ecosystems for the purpose of research, conservation, education and display. These are generally known as a bio-shelters or ecoriums. The Wikipedia defines a bio-shelter as ―A bio-shelter is a solar greenhouse managed as an indoor ecosystem.‖3 Figure 2-1: Biomes of The Eden Project 1 (Basic, Greenhouse), Primary Industries Agriculture (Conservatory), Wikipedia 3 (Bioshelter), Wikipedia 2 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 9 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 2.2. History As mentioned in Wikipedia, the history of greenhouses dates back to the 13th century. They were built in Italy to house the exotic plants that explorers brought back from the tropics and were originally called giardini botanici (botanical gardens). ‗Active‘ greenhouses, in which it is possible for the temperature to be increased or decreased manually, appeared much later.4 The French botanist Charles Lucien Bonaparte is often credited with building the first practical modern greenhouse in Leiden, Holland during the 1800s to grow medicinal tropical plants. Originally only on the estates of the rich, the growth of the science of botany caused greenhouses to spread to the universities. The French called their first greenhouses orangeries, since they were used to protect orange trees from freezing. As pineapples became popular, pineries, or pineapple pits, were built. Experimentation with the design of greenhouses continued during the 17th century in Europe, as technology produced better glass and construction techniques improved. The greenhouse at the Palace of Versailles was an example of their size and elaborateness; it was more than 500 feet (150 m) long, 42 feet (13 m) wide, and 45 feet (14 m) high.5 The golden era of the greenhouse was in England during the Victorian era, where the largest glasshouses yet conceived were constructed, as the wealthy upper class and aspiring botanists competed to build the most elaborate buildings. A good example of this trend is the pioneering Kew Gardens. Joseph Paxton, who had experimented with glass and iron in the creation of large greenhouses as the head gardener at Chatsworth, in Derbyshire, working for the Duke of Devonshire, designed and built The Crystal Palace in London, (although the latter was constructed for both horticultural and non-horticultural exhibition).6 In the 20th century, the geodesic dome was added to the many types of greenhouses. Notable examples are the Eden Project, in Cornwall, The Rodale Institute in Pennsylvania, at the Missouri Botanical Garden in St. Louis, Missouri, and Toyota Motor Manufacturing Kentucky. Greenhouse structures adapted in the 1960s, when wider sheets of polyethylene film became widely available. Hoop houses were made by several companies and were also frequently made by the growers themselves. Constructed of aluminum extrusions, special galvanized steel tubing, or even just lengths of steel or PVC water pipe, construction costs were greatly reduced. This resulted in many more greenhouses being constructed on smaller farms and garden centers. Polyethylene film durability increased greatly when more effective UV-inhibitors were developed and added in the 1970s; these extended the usable life of the film from one or two years up to 3 and eventually 4 or more years. Gutter-connected greenhouses became more prevalent in the 1980s and 1990s. These greenhouses have two or more bays connected by a common wall, or row of support 4 (Greenhouse), Wikipedia Ibid, (Greenhouse) 6 Ibid, (Greenhouse) 5 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 10 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE posts. Heating inputs were reduced as the ratio of floor area to roof area was increased substantially. Gutter-connected greenhouses are now commonly used both in production and in situations where plants are grown and sold to the public as well. Gutter-connected greenhouses are commonly covered with structured polycarbonate materials, or a double layer of polyethylene film with air blown between to provide increased heating efficiencies.7 2.3. Working principles A greenhouse works primarily by preventing absorbed heat from leaving the structure through convection, i.e. sensible heat transport. A greenhouse is built of any material that passes sunlight, usually glass, or plastic. It mainly heats up because the Sun warms the ground inside, which then warms the air in the greenhouse. The air continues to heat because it is confined within the greenhouse, unlike the environment outside the greenhouse where warm air near the surface rises and mixes with cooler air demonstrated aloft. This by opening can a be small window near the roof of a greenhouse: the temperature will drop considerably. Thus greenhouses work primarily by preventing convective cooling. 2.4. Figure 2-2: Working principles of greenhouses General design considerations 2.4.1. Siting As the working principle of greenhouse depends upon the solar energy, the orientation towards south is the best. Shadows cast by gutters, trusses and equipment in the roof of the greenhouse can lead to uneven light conditions in the plants. An east-west alignment creates structural shadows in the same part of the plant through the day which can affect plant health in this area. Subsequently, to minimize shading effects, greenhouses are generally oriented north-south. 8 The direction of prevailing winds should be taken into consideration, with structures oriented to take advantage of cooling summer breezes. When siting a greenhouse, consideration of the shading effect of vegetative screens and windbreaks should be taken. Also, the availability of water resources and other complimentary accessories for the greenhouse operation should be taken under considerations. 7 8 Ibid, (Greenhouse) (Basic, Greenhouse), Primary Industries Agriculture EMIL SHRESTHA; 66011, B. Arch. 066, V/I 11 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 2.4.2. Height of greenhouse structure Height is one of the most important aspects of a greenhouse. The height of a structure directly impacts on natural ventilation, the stability of the internal environment. Greenhouse structures with wall heights of at least 4 meters should be constructed wherever feasible. These structures should be built in preference to designs of lower height. The natural ‗chimney effect‘ of rising hot air and falling cooler air which is the basis for passive ventilation becomes truly effective above approximately 3.5 meters.9 A tall, roof ventilated greenhouse can achieve a more uniform, stable and ultimately superior growing environment for the crop. During hot weather, a taller structure avoids trapping heated, humid air around the plants. Although some plants can be grown relatively well in lower profile greenhouses, taller structures are more versatile, are suitable for a wider range of plants and therefore a better long term investment. 2.4.3. Framework The main difference between the materials used for the frameworks depends upon the durability of the structure, aesthetics and need of regular maintenance. The frameworks should be light in construction. 2.4.3.1. Aluminium Aluminum is widely used as a framing material due to its no maintenance required. Also, it is durable and lighter in weight for the construction. Aluminum profiles are coated for desired colors of the structure. But these frames are poor in thermal insulation 2.4.3.2. Timber The most popular type of timber used for greenhouses is cedar but softwood is also used. Timber frames marginally conserve heat more than other frame materials used for greenhouses. But, these frames need frequent maintenance, as the wood tends to rot along with the time. So, before use the wood should be well seasoned, and treated well with preservatives to prevent from rots and termites. 2.4.3.3. Steel Steel is the forerunner to the present day aluminum extruded framework. The original steel greenhouses meant putty had to be used to fix glass which is not ideal if glass breakage is experienced. Steel frames however are used in tubular form to support Poly tunnels on which sheets of polythene are stretched. 9 (Height, Greenhouse), Primary Industries Agriculture EMIL SHRESTHA; 66011, B. Arch. 066, V/I 12 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 2.4.4. Coverings 2.4.4.1. Glazing Glazing medium selected must be capable of high light transmission while also holding heat gain or loss to minimum. These materials should be strong enough to resist the local wind and snow impacts. a. Toughened safety glass It is harder to break but if it does, it will do so safely into very small fragments, similar to the side windows of modern cars. Toughened glass offered by some manufacturers is 3mm thick and the best use 4mm thick. It has impact strength of up to 5 times greater than that of ordinary glass of the same thickness. b. Clear acrylic This glazing material of 2mm or 3mm thickness is generally used for curved eaves designed greenhouses. This material is cheap than others but has a short life span and does get very brittle. Also, acrylic creates an abundance of static which draws dust to both surfaces and in turn very much reduces valuable light entering the greenhouse. c. Polycarbonate sheets This tough, twin walled material is shatterproof and is offered generally in 4mm or 6mm thick for greenhouses. The additional benefit of Polycarbonate is that it has an excellent insulating property which is Figure 2-3: Double polycarbonate ideal for cold climatic zones. But this material is very sheets expensive. d. Fiberglass reinforced plastic (FRP) Fiberglass is composed of glass fibres embedded in a polyester resin. Fiberglass sheets are less expensive than glass but more expensive than polyethylene. They are lightweight and impact resistant compared to glass. They have a fairly high light transmittance that is slightly less than that of glass and polyethylene, and fiberglass covered greenhouses are easy to fabricate. FRP sheets degrade when exposed to ultraviolet light. Their ultraviolet resistance is improved by the use of polyvinyl fluoride coatings and acrylic additions to the polyester resin.10 10 (Bucklin), Physical Greenhouse Design Considerations - Florida Greenhouse Vegetable Production Handbook EMIL SHRESTHA; 66011, B. Arch. 066, V/I 13 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE e. Double poly When double polyethylene film is used, this system is called double poly. Double poly construction utilizes a small fan to inflate the area between the two layers. This dead air space greatly improves the insulating properties of the greenhouse. When compared to a single layer of polyethylene film, the double poly system reduces heat loss or gain by 35%-40% with a 10% reduction in light transmission. A tightly inflated double poly greenhouse is more resistant to wind damage than a single poly house and most fiberglass greenhouses; however, a double poly greenhouse requires more maintenance to keep the double poly system properly inflated and a good poly lock system is required to seal the layers of polyethylene together at their seams.11 In addition: • Colour pigments may improve plant growth by altering the proportion of selected wavelength ranges. • Fluorescence may be used to increase the emission of red light. • Glossy surfaces may repel insects. 2.4.4.2. Protective screen fabrics a. Shade cloth This reduces the amount of solar energy entering the greenhouse, which lowers plant stress reduces light intensity will protect structures from hail damage. If shading is required, pale coloured materials should be used as these uniformly reflect solar radiation. A range of products exist that offer shading from 30% up to almost total blackout. Whitewash paints are another option that can be applied to reduce the amount of radiation entering the greenhouse.12 b. Solar and thermal screen This reduces the amount of solar radiation incident on the plants or prevents the escape of long wave radiation from the greenhouse and trap warm air. The first use allows some radiation to penetrate and reflects the rest. This is used for temperature control during the day. The second type retains energy within the greenhouse and is used at night. Thermal screens are typically drawn over the crop or structure when needed.13 c. Insect-proof screen This excludes insect pests, reducing the need for chemicals. Restricted airflow is the main disadvantage. The type of screen used will depend on the insects to be excluded. Plastic screens eventually suffer from the same UV deterioration as plastic films.14 11 Ibid, (Bucklin) (Covers, Greenhouse), Primary Industries Agriculture Ibid, (Covers, Greenhouse) 14 Ibid, (Covers, Greenhouse) 12 13 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 14 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 2.4.5. Ground cover Greenhouses can have very simple flooring made of wooden slats, or even a pressed dirt floor. Where conservatories usually have finished floors, work-a-day greenhouses will often have dirt around the perimeter and pea shingle, wood, concrete or stone walkways. Concrete or any other hard surfaced walkways between rows in the greenhouse and between buildings not only facilitate moving materials but can improve sanitation. Walkways control the movement of traffic into and around the production area and can minimize tracking contaminated soil or plant material into the greenhouse. This is an important consideration because prevention of nematode infestation is a much surer management strategy than any curative treatment. For soil or bag plant growing, there must be a permanent barrier between the crop and the native soil beneath the house. Native soils have populations of nematodes and pathogens that are easily introduced into greenhouse operations and very difficult to control. Any of several root nematodes and other vegetable nematodes are commonly found in most native soils. They can get into a greenhouse whenever the barrier between the crop and the native soil beneath the house is broken. 2.4.6. Adjacent Facilities Adjacent facilities for properly storing and handling growing media should be provided. Any component of the growing media that was never sterilized or has been exposed to contamination during storage and handling can introduce nematodes. Concrete bins that are cracked, allowing weed roots to grow through from native soil, can carry infestation into the soil mix. Run-off from heavy rains, contaminated with field soil, that flows across the storage or mixing area can also do the job. Using machinery that has been used for field operations to mix or move growing media can contaminate it. If transplants will be produced on site, a totally sterile facility should be built for that purpose. 2.5. Types of Greenhouse 2.5.1. Shape and design The shape and design of the structure influences: • the amount of light transmitted • the amount of natural ventilation • the useable internal space • efficient use of structural materials • condensation run-off • heating requirements • the cost. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 15 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Classification of a greenhouse is according to its basic shape. 2.5.1.1. Gable (single span) A multi-span provides greater internal space that can be more readily managed than a number of single free standing greenhouses. 2.5.1.2. Gable (multi-span) Multi-spans are efficient in terms of heat energy requirements because the total surface area is less than that needed for single spans of the same floor area. The distance from the sides to the centre of a multi-span, however, can present a ventilation problem and overheating can occur in the centre of a multi-span. 2.5.1.3. Saw tooth The saw tooth is erected with the vertical side of the ridges facing away from the prevailing wind. The design provides effective, natural removal of hot air from the greenhouse. Figure 2-4: Structural types of Greenhouse 2.5.1.4. Skillion The flat roof design transmits the least amount of light due to the reflection of light when the sun is low. Curved roofs offer the greatest annual light transmission but ventilation is less effective as the flat ‗apex‘ can trap hot air. 2.5.1.5. Tunnel (igloo) The relatively cheap igloo is the most common structure. Adequate ventilation is often lacking with this design which increases crop stress. 2.5.1.6. Flat arch The flat arch adds height to the tunnel structure, stabilizing the internal environment and the vertical walls increase the area of useable internal space. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 16 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 2.5.1.7. Raised dome The raised dome incorporates more height into the tunnel design. Height increases the inside volume of air which makes the environment more stable. This reduces temperature fluctuations and reduces plant stress. Higher walls increase construction and heating costs and increase the wind load on the structure, but the advantages of height tend to over-ride any disadvantages. A rule of thumb is to have vents at least 3.6 meters above the ground level to improve natural ventilation.15 2.5.1.8. Geodesic shape The triangle shapes forming the growing dome create a geometric pattern of strength not replicated in a simple rectangular shape. This shape is incredibly wind friendly as the wind simply flows around it. The curved surface of the dome allows for a very even heat input by the sun throughout the day. The round shape also handles snow effortlessly because it allows snow to slide off naturally. A spherical shape has the minimum surface area for the amount of floor space enclosed. The dome is much more effective at keeping the heat in on a cold winter night simply by having a lot less surface area through which the heat can escape. Figure 2-5: Example of a geodesic dome 2.5.2. Other types of structures 2.5.2.1. Shade houses Shade houses are structures which are covered in woven or otherwise constructed materials to allow sunlight, moisture and air to pass through the gaps. The covering material 15 (Structures types, greenhouse), Primary Industries Agriculture EMIL SHRESTHA; 66011, B. Arch. 066, V/I 17 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE is used to provide a particular environmental modification, such as reduced light or protection from severe weather conditions. The height of the structure will vary according to the type of plants being produced and may be as high as 8 meters. Shade houses are used over outdoor hydroponic systems, particularly in warmer regions. 2.5.2.2. Screen houses Screen houses are structures which are covered in insect screening material instead of plastic or glass. They provide environmental modification and protection from severe weather conditions as well as exclusion of pests. They are often used to get some of the benefits of greenhouses in hot or tropical climates. 2.5.2.3. Plant top structures A plant top is a structure with a roof but which does not have walls. The roof covering may be a greenhouse covering material such as plastic or glass, or shade cloth or insect screening. These structures provide some modification of the growing environment such as protection of the plant from rain or reduction of light levels. 2.6. Utilities and services Figure 2-6: General utilities and services in greenhouse EMIL SHRESTHA; 66011, B. Arch. 066, V/I 18 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 2.6.1. Greenhouse heating Heating considerations is the most important in the operation of the greenhouses. The main problem with heating a greenhouse is the amount of heat lost through the greenhouse covering. Since the coverings need to allow light to filter into the structure, they conversely cannot insulate very well. Most greenhouses, when supplemental heat is needed use natural gas or electrical furnaces. Passive heating methods exist which seek heat using Figure 2-7: General heat loss in greenhouse low energy input. Solar energy can be captured from periods of relative abundance (day time/ summer), and released boost the temperature during cooler periods (night time/winter). Waste heat from livestock can also be used to heat greenhouses; e.g. placing a chicken coop inside a greenhouse recovers the heat generated by the chickens, which would otherwise be wasted. Following things are to be considered when heating system is to be implemented.16 • Accurate and efficient temperature and humidity control. • The heat supply must be suited to the plants‘ requirements. • The heating system must be suited to the energy sources available in the region. • Uniform heat dispersal in all the greenhouses. After the calculation of the total heat required, the size of the burner, the boiler and the heat dispersal system are determined. Greenhouse heat requirements are determined by: • Crop heat requirements, • Minimum means temperature in the region, • Expected heat loss from the greenhouse. Generally two heating options are implemented in greenhouses: 2.6.1.1. Hot water method This heating method is partly based on direct radiation, in which parts of the plant receive direct radiation from the heating pipes (steel or aluminum pipes). The water temperature is normally controlled by 3- 4-way valves, which control the ratios of hot and cold water. The system enables the establishment of a continuous temperature regimen, with few fluctuations. Another advantage is that heat dispersal inside the greenhouse is uniform. Control and command are carried out by the central system computer. Conducting the water in steel pipes is also a convenient method for transporting trolleys over the pipes, thus improving efficiency.17 16 17 (Greenhouse Technology, Heating), Netafim Ibid, (Greenhouse Technology, Heating) EMIL SHRESTHA; 66011, B. Arch. 066, V/I 19 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 2.6.1.2. Hot air method The burner causes combustion in the burning cell. Heat thus produced is ejected and passes over the external walls of the burning cell by radiation and convection. Cold air passing over the burning cell is sucked into the greenhouse cavity, is heated and is then released through the sleeves into the greenhouse. The air circulation process is executed by a centrifugal blower operated by electric motor. Heat in the greenhouse is dispersed through a system of perforated Figure 2-8: Normal air heater used for greenhouse polyethylene sleeves. 18 2.6.2. Greenhouse cooling During summer, the temperature inside the structure gets high, due to the trapping of the un-escaped convections. Hence, cooling systems are required to drop the temperature down as favorable for the growth of the plants. Technically, three methods are used for cooling and reducing greenhouse temperatures: 2.6.2.1. Air exchange Air exchange is done between the air inside the greenhouse and the outside atmosphere. This exchange is accomplished either passively through roof and side vents, or actively by operating ventilators that increase the rate of air exchange when natural air exchange is insufficient for the plant‘s requirements.19 2.6.2.2. Adiabatic cooling This increases the humidity while lowering the temperature inside the greenhouse. a. Cool net foggers A super-fine mist sprayer is highly suitable for rooting and does not wet plant leaves, operates at accepted working pressures. These deliver an ultra-small drop size of 80 microns at a pressure of 4 bars. Used in extremely short water bursts, it can reduce the ambient temperature by 5-10°C (depending on atmospheric conditions, relative humidity and/or temperature). These can also be used for chemical applications. This system includes cool-net emitters with microsized droplets of 80-90 micron, anti-drainage valve, fans, pipe system for water supply.20 18 Ibid, (Greenhouse Technology, Heating) (Greenhouse Technology, Cooling), Netafim 20 Ibid, (Greenhouse Technology, Cooling) 19 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 20 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE b. Wet-pads Fan and pad systems combine two pieces of equipment. An exhaust fan is located at one end of the greenhouse and a porous pad is built into the wall of the structure at the opposite end. A pump circulates water over and through the pad. When the fan is in operation, it pulls air from outside the structure, through the evaporative pad, into the greenhouse. The air, passing through and over the wet pad evaporates some of the water and is cooled. As a result, cool air is drawn into the greenhouse to replace the hot air expelled by the fan.21 These systems are quite effective for cooling but are relatively expensive to install and maintain. A disadvantage of the fan and pad system is that it tends to create a significant temperature gradient from one end of the greenhouse to the other (warmest at the fan end and coolest at the pad end). 2.6.2.3. Reducing radiation penetration This method uses stationary or movable shade screens. By reducing the intensity of radiation penetration, the heat inside the greenhouse is decreased. Radiation reduction also cuts down light penetration, essential to the plant‘s photosynthesis process. This conflict can be optimized by using moveable screens operated automatically or manually, and/or screens with relatively low shading percentages. The shading rate can be adjusted to between 20% and 80% depending on climatic conditions and type of plants.22 The most common shade screens are black. 2.6.3. Greenhouse ventilation Ventilation is one of the most important components in a successful greenhouse. If there is no proper ventilation, greenhouses and their plants can become prone to problems. The main purposes of ventilation are to regulate the temperature to the optimal level, and to ensure movement of air and thus prevent build-up of plant pathogens (such as Botrytis cinerea) that prefer still air conditions. Ventilation also ensures a supply of fresh air for photosynthesis and plant respiration, and may enable important pollinators to access the greenhouse plants. Air movement in the greenhouse should be between 0.2 and 0.7 meters per second. If carbon dioxide levels are not maintained, plant growth is affected. Ventilation can be achieved passively or actively. The venting capacity of greenhouses is usually described as a percentage of floor area. For example, a greenhouse with 30% roof ventilation has 0.3m2 of open vent area for every 1m2 of floor area. It is better to have more venting capacity than needed. Usually, about 20%of roof area is provided with ventilation strips or individual opening windows. For proper natural ventilation in sloped roofed greenhouses the roof must 21 Ibid, (Greenhouse Technology, Cooling) Ibid, (Greenhouse Technology, Cooling) 22 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 21 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE be sloped between 3:12 to 6:12. This will normally result in a higher roof than is required for mechanical ventilation. The natural ‗chimney effect‘ of rising hot air and falling cooler air which is the basis for passive ventilation becomes truly effective above approximately 3.5 meters. A low profile greenhouse therefore, will require forced cooling to provide similar suitable conditions to a tall structure.23 2.6.3.1. Fans Active ventilation is the use of equipment to force air into or out of the structure. Fans are the key method of actively venting a greenhouse. Fans can also be fitted in greenhouses to move or circulate air within the greenhouse. Circulating fans are often used inside passively ventilated structures to assist air movement when venting is minimal. When using fans for air exchange, the most effective approach is to pull the air through the full length of the structure to avoid hot air pockets remaining. Fans placed to extract air from higher in the greenhouse are more effective for cooling than fans which are placed lower. Active ventilation systems are limited in their capacity to quickly exchange large volumes of air. Under ventilated structures often have overheating problems in the plants in the middle of the greenhouse. Ventilation fans generally need to have sufficient capacity to completely replace the air in the greenhouse every minute. Fans have an on-going operational cost and noise generation may pose problems in some areas. Fan efficiencies influence running costs and should be considered when using. It is important to clean and maintain fans to ensure that they are functioning properly. 2.6.4. Greenhouse Plant growing Various plants growing techniques are widely used in greenhouses. Plants can be grown on the ground, on the bed created, pots or on substrates. Usually, beds are created for plants growing purposes with drainage system provided. For plants to grow on pots, benches are used. Lately soilless substrates are used for growing plants in large scales. 2.6.4.1. Growing in soilless substrates The Advantages 23 • Enhanced control of water and fertilizer applications • Optimal moisture in the substrate • Optimal nutrient supply • Significant advantage in disinfecting between growing periods • Water recycling enables reduced expenses (Ventilation, Greenhouse), Primary Industries Agriculture EMIL SHRESTHA; 66011, B. Arch. 066, V/I 22 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE • Excellent alternative when soil is not suitable for growing crops due to salinity, drainage problems, etc. The Limitations • Low root volume • Low nutrient storage • Trace elements - important to control • Low buffering capacity • Fast changes in pH The ideal substrate must have high water capacity and mobility, along with high air content. They should be light weight, stable and should have high capacity to supply nutrients. To make efficient use of a substrate, it is necessary to be familiar with its physical and chemical properties; and to enable optimal irrigation and fertilization interface applications. 2.6.4.2. Substrate Types a. Inorganic Substrates Some inorganic substrates are inert. They do not decompose, are not chemically active, have low buffer capacity and exchangeable cation content, and contain no organic material that enables micro-biological activity. In these, chemical changes are quick, necessitating intensive irrigation and fertilizer control. This group includes rock wool, perlite, styro-foam and sponge.24 Mineral substrates that react chemically, absorb and release nutrients, have a medium buffer capacity, and are therefore involved in plant nutrition. This group includes volcanic ash, pumice and vermiculite. b. Organic Substrates These are composed of organic materials that absorb and release nutrients to plants, have relatively high buffer capacity and exchangeable cation content compared to inert materials. In these chemical changes is slower, requiring less intensive control. This group includes coco peat, peat moss, composts and other organic mixtures. 2.6.4.3. Plants growing containers 24 • Buckets • Foamed polystyrene containers • Continuous polypropylene containers • Gutters • Grow bags (Greenhouse Technology, Growing methods), Netafim EMIL SHRESTHA; 66011, B. Arch. 066, V/I 23 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE In containers drainage is to be considered. If containers are large, needed slopes are to be maintained for the drainage. While selecting a container following things are to be considered. • Allowance for resistance to chemical and steam disinfection processes must be made. • Containers must be made of UV radiation resistant material. • Most soilless substrates require relatively high and frequent irrigation applications to balance the air-water ratio. • It is critical to ensure that spacing between drippers is relatively small, and that low flow rates and anti-drain properties are maintained. 2.6.5. Greenhouse irrigation and nutrition A well maintained irrigation system is required to reduce water stress which occurs due to inadequate water and also from too much water (flooding). Flooding deprives roots of oxygen that is required for proper root function. The modern advancement in technologies has helped to create wide range of sensors and equipment for determining plants' water requirements. Designing greenhouse irrigation systems based on water and nutrient plant demands:25 • Accurate water and nutrient applications • The system enables the grower to adjust water and fertilizer applications according to changing plant needs. Operating accuracy, reliability, functionality and convenience are the main considerations to be made in irrigation systems.26 • Irrigation strategy is determined by: • Climate conditions, substrate properties • Plant development status, water quality 2.6.5.1. Water recycling Growing crops in a soilless substrate appears wasteful in terms of water and fertilizer because in order to properly flush the substrate, it is necessary to apply 30%-50% more water than the evapo-transpiration rate (plant requirements). However the drained water can recycle for further use. Recycling technologies offer several advantages: significant water and fertilizer savings (50%-70%), enhanced quality yields, (as the result of increasing water applications), improved availability of nutrients and more efficient flushing, which reduces ground water contamination and ecological damage in agronomic regions.27 25 (Greenhouse Technology, Iirrigation nutrition), Netafim Ibid, (Greenhouse Technology, Iirrigation nutrition) 27 Ibid, (Greenhouse Technology, Iirrigation nutrition) 26 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 24 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Recycling Methods • Collecting drainage water from a soilless substrate, and using it to irrigate an adjacent crop grown in soil (open system). • Recycling drainage water in a closed system; with or without disinfecting the drainage water. • Recycling drainage water diluted with rain water or with desalinated water. • 2/3: 1/3 method: the drainage water discharged from 2/3 of the greenhouse can be used to irrigate the remaining third (a common method in roses). 2.6.6. Lightings The amount of light entering a greenhouse is influenced by; • the orientation of the structure • the materials used in construction and covers • the shape of the roof Diffuse light is better than direct light because it is able to reach the lower parts of the canopy (less shadowing) and it will not cause sunburn. The selected covering material may also be used to increase the amount of diffuse light. A textured surface on glass, for example, can increase the proportion of diffuse light without significantly reducing the total level of light transmitted. Figure 2-9: Relationship between light and photosynthesis process Colored films The color of plastic films affects the total level of light that enters the greenhouse. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 25 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE A clear film will transmit the most amount of light. Blue and green colored plastics will transmit a lot of the light in the blue to blue-green wavelengths, but cut out much of the light in the red wavelengths. From the diagram above looking at PAR, it can be seen that red light is the most efficient waveband for plant growth. A blue plastic is likely to produce a slower growing, shorter, tougher plant.28 Also of interest is that plants have been shown to use far-red light as a way of determining how much competition there is for light. This is because green surfaces, such as leaves from other plants, reflect a lot of far-red light. If the plant perceives that there is a lot of competition, it will put less energy into growing roots and more into growing tall, quickly.29 A green plastic is likely to produce a stretched, slow growing, poor performing plant. A white film will reduce the total amount of light transmitted by as much as 20%, but the light spectrum entering the greenhouse will remain similar to the natural 30 spectrum. 2.7. light Figure 2-10: Example of a well-lit greenhouse Other features a. Fans Generally, two distinct fans are used in a greenhouse. An air-circulating fan does what the name implies — gently circulating the air to prevent stagnant spots or stale air. It keeps air moving throughout the structure. This fan runs constantly, 24 hours a day, to keep air moving at all times. A heat-saver fan mounted up high pulls hot air from the roof of the greenhouse and circulates it downward to provide warmth in the areas where the plants are. b. Humidity Dial Figure 2-11: Example of a greenhouse environment monitoring device A humidity dial is an essential accessory. It keeps a constant reading on how much moisture is in the air. Many plants such as orchids and other tropical plants thrive best at specific levels of humidity. 28 (Light, Greenhouse), Primary Industries Agriculture Ibid, (Light, Greenhouse) 30 Ibid, (Light, Greenhouse) 29 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 26 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE c. 4-Way Analyser A 4-way analyzer uses a probe that is inserted into a plant's soil. The readout on the meter indicates levels of moisture, light, pH content and soil nutrients. This device will help you know if a particular plant needs more or less light, water or fertilizer. d. Light Meter A light-intensity meter uses a probe placed in proximity to a plant to indicate the level of light being received. The sensor uses a photovoltaic cell, so no batteries are necessary. e. Thermostat A specialized electric heater that is moisture resistant and has a very sensitive and accurate thermostat for maintaining a constant and even temperature inside the greenhouse maintains the climate. It can be mounted to the wall. f. Starter Trays Seed-starter trays, used in conjunction with a heated seed-mat and suspended light, are used to germinate seedlings in the spring. The clear domes on top of the trays help contain moisture to prevent the seeds or new plants from drying out. g. Control Monitors Heat on Seeds A thermostatic control for the heat mat ensures that seeds and seedlings are maintained at the ideal temperature for germination and growth. h. Misting System An automatic misting system installed throughout the greenhouse simplifies watering, and (when used on a timer) provides water when you're away. i. Electronic Monitor An electronic monitoring station has a radio-controlled clock precisely set to a U.S. atomic clock. The readout on the meter indicates temperature and humidity readings in the greenhouse where the sensor is placed. The meter operates remotely from the sensor, and has a range of up to 300'. In this way, you can check the conditions in your greenhouse from inside your home. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 27 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Plants Study 3. 3.1. Introduction A plant is a living organism that generally does not move and absorbs nutrients from its surroundings. Plants are one of the two groups, as divided by Aristotle (384 BC -322 BC), into which all living things were traditionally divided; the other is animals. But later, various scientific classifications has defined several groups which have cleared the concept of plants and other living organisms like fungi, algae etc. However, these organisms are still often considered plants, particularly in popular contexts. Outside of formal scientific contexts, the term "plant" implies an association with certain traits, such as being multicellular, possessing cellulose, and having the ability to carry out photosynthesis.31 3.2. Plant Taxonomy Plant taxonomy is the science that finds, identifies, describes, classifies, and names plants. Plant taxonomy is a controversial field, traditionally not having any close agreement on circumscription and placement of taxa. 3.2.1. Identification, classification and description Plant identification is the determination of the identity of an unknown plant by comparison with previously collected specimens or with the aid of books or identification manuals. Plant classification is the placing of known plants into groups or categories to show some relationship.32 Scientific classification follows a system of rules that standardizes the results, and groups successive categories into a hierarchy. For example, the family to which the lilies belong is classified as follows:33        Kingdom: Plantae Division: Magnoliophyta Class: Liliopsida Order: Liliales Family: Liliaceae Genus: ...... Species: ...... Plant description is a formal description of a newly discovered species, usually in the form of a scientific paper. 31 (Plants), Wikipedia (Plant Taxonomy), Wikipedia 33 Ibid, (Plant Taxonomy) 32 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 28 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 3.2.2. Binomial nomenclature According to binomial system of nomenclature, the scientific name of an organism consists of two separate components, first one designates the genus (generic name) and the second one designates the species (specific name). The generic name starts with a capital letter and specific name starts with a small letter. They must be underlined if hand written or typed in an italic font. For example, the scientific binomial name of rice is Oryza sativa, when first name Oryza is generic and the second name sativa is specific. 3.3. Vegetative and reproductive characteristics The vegetative (somatic) structures of vascular plants include two major organ systems: (1) a shoot system composed of stems and leaves, and (2) a root system. By contrast, the reproductive structures are varied, and are usually specific to a particular group of plants. Structures such as flowers and fruits are only found in the angiosperms; sori are only found in ferns; and seed cones are only found in conifers and other gymnosperms.34 Figure 3-1: Plants vegetative characteristics 3.4. Plants propagation Plant propagation is the process of creating new plants from a variety of sources: seeds, cuttings, bulbs and other plant parts. Plant propagation can also refer to the artificial or natural dispersal of plants. 3.4.1. Sexual propagation (seed) Seeds and spores can be used for reproduction (through e.g. sowing). Seeds are typically produced from sexual reproduction within a species. A plant grown from seeds may have different characteristics from its parents. Some species produce seeds that require special conditions to germinate, such as cold treatment. Some plant species, including 34 (Plant Morphology), Wikipedia EMIL SHRESTHA; 66011, B. Arch. 066, V/I 29 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE many trees do not produce seeds until they reach maturity, which may take many years. Seeds can be difficult to acquire and some plants do not produce seed at all.35 3.4.2. Asexual propagation Plants have a number of mechanisms for asexual or vegetative reproduction. People also use methods that plants do not use, such as tissue culture and grafting. Plants are produced using material from a single parent and as such there is no exchange of genetic material, therefore vegetative propagation methods almost always produce plants that are identical to the parent. Vegetative reproduction uses plants parts such as roots, stems and leaves. In some plants seeds can be produced without fertilization and the seeds contain only the genetic material of the parent plant.36 Techniques for vegetative propagation include:  Air or ground layering  Division  Grafting and bud grafting, widely used in fruit tree propagation  Micro propagation  Storage organs such as bulbs, corms, tubers and rhizomes  Striking or cuttings  Twin-scaling 3.5. Ecological distribution of plants Plant communities are broadly distributed into biomes based on the form of the dominant plant species. Biomes are determined by regional climates, mostly temperature and precipitation, and follow general latitudinal trends. Within biomes, there may be many ecological communities, which are impacted not only by climate and a variety of smaller-scale features, including soils, hydrology, and disturbance regime. Biomes also change with elevation, high elevations often resembling those found at higher latitudes. Figure 3-2: Ecological Distribution of terrestrial biomes 37 35 (Plant Propagation), Wikipedia Ibid, (Plant Propagation) 37 (Natural Vegetation In The World Regent Secondary), Slideshare 36 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 30 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Figure 3-3: Climatic data in the various terrestrial biomes 38 3.5.1. Tropical rainforests These have little climatic variation—no seasons and no cold nor dry period–and are either tradewind type (with steady, almost daily rains) or equatorial(with frequent, heavy thunderstorms). Mean monthly temperatures are above 64 ° F; precipitation is often in excess of 100 inches a year. Vegetation A vertical stratification of three layers of trees is apparent. The emergent are widely spaced trees 100 to 120 feet tall and with umbrella-shaped canopies extend above the general canopy of the forest. The other is a closed canopy of 80 foot trees. Light is readily available at the top of this layer, but greatly reduced below it. The last is a closed canopy of 60 foot trees. There is little air movement in this zone and consequently humidity is constantly high.39 Shrub sapling layer: Less than 3 percent of Figure 3-4: Tropical rainforest the light intercepted at the top of the forest canopy passes to this layer. Arrested growth is characteristic of young trees capable of a rapid surge of growth when a gap in canopy above them opens.40 38 (Distribution of Vegetation), Cliffsnotes (Tropical Rainforest), Biomes of the World, Department of Geospatial Science, Radford University 40 Ibid, (Tropical Rainforest) 39 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 31 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Figure 3-5: Plant layers in the rainforest Ground layer: Sparse plant growth. Less than 1 percent of the light that strikes the top of the forest penetrates to the forest floor. In such darkness few green plants grow. Moisture is also reduced by the canopy above: one third of the precipitation is intercepted before it reaches the ground.41 Growth forms Various growth forms represent strategies to reach sunlight:42  Epiphytes: the so-called air plants grow on branches high in the trees, using the limbs merely for support and extracting moisture from the air and trapping the constant leaf-fall and wind-blown dust. Bromeliads (pineapple family) are especially abundant in the neo-tropics; the orchid family is widely distributed in all three formations of the tropical rainforest.  Lianas: woody vines grow rapidly up the tree trunks when there is a temporary gap in the canopy and flower and fruit in the tree tops of the emergent and canopies layers. Many are deciduous.  Climbers: green-stemmed plants such as philodendron that remain in the understory.  Stranglers: these plants begin life as epiphytes in the canopy and send their roots downward to the forest floor. The fig family is well represented among stranglers. 3.5.2. Tundra This occurs north of the tree line and principally north of the Arctic Circle in an area of low precipitation and little snow with cold average temperatures. Vegetation consists of small perennial herbs, low shrubs, creeping willows, and a variety of grasses, sedges, mosses and lichens.43 Figure 3-6: Tundra vegetation 41 Ibid, (Tropical Rainforest) Ibid, (Tropical Rainforest) 43 (Terrestrial Biomes Of The World), Cliffsnotes 42 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 32 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Vegetation Common vegetation found are lichens, mosses, sedges, perennial forbs, and dwarfed shrubs, (often heaths, but also birches and willows).44 Growth forms Typical are ground-hugging and other warmth-preserving forms including:45  tussock-forming graminoids  mats or cushion plants, often evergreen members of the heath family  rosettes  dwarf shrubs, some of which are deciduous in habit 3.5.3. Taiga (Coniferous) It is the Russian name for the coniferous forest that forms a wide belt between the tundra of the north and the temperate deciduous forest to the south. It is composed primarily of species of pine, spruce, and fir with an understory of ericaceous shrubs (heaths), mosses, and lichens.46 Vegetation Needle-leaf, coniferous (gymnosperm) trees are the dominant plants of the taiga biome. A very few species in four main genera are found: the evergreen spruce (Picea), fir (Abies), and pine (Pinus), and the deciduous larch or tamarack (Larix). In North America, one or two species of fir and one or two species of spruce are dominant. Across Scandanavia and western Russia the Scots pine is a common component of the taiga.47 Growth forms Figure 3-7: Taiga vegetation The conical or spire-shaped needle-leaf trees common to the taiga are adapted to the cold and the physiological drought of winter and to the shortgrowing season:48  Conical shape – promotes shedding of snow and prevents loss of branches.  Needle-leaf – narrowness reduces surface area through which water may be lost (transpired), especially during winter when the frozen ground prevents plants from replenishing their water supply.  Evergreen habit – retention of foliage allows plants to photosynthesize as soon as temperatures permit in spring, rather than having to waste time in the short growing season merely growing leaves  Dark color – the dark green of spruce and fir needles helps the foliage absorb maximum heat from the sun and begin photosynthesis as early as possible. 44 (Tundra), Biomes of the World, Department of Geospatial Science, Radford University Ibid, (Tundra) 46 Op. cit. (Terrestrial Biomes Of The World) 47 (Boreal Forest (Taiga)), Biomes of the World, Department of Geospatial Science, Radford University 48 Ibid. (Boreal Forest (Taiga)) 45 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 33 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 3.5.4. Temperate deciduous forest It is a mixture of broad‐leaved deciduous trees (such as beech, maples, and oaks) together with species of perennial herbs. Seasons are pronounced with precipitation distributed evenly throughout the year.49 The shortening days of fall stimulate the plants to withdraw chlorophyll from their leaves, allowing a brief but beautiful display of other pigments before the leaves are shed completely and plants enter an extended period of dormancy. Vegetation Many of the same genera, previously part of an Arcto-Tertiary Geoflora, are common to all three of the disjunct northern hemisphere expressions of this biome. Included among these genera are: Quercus (oak), Acer (maple), Fagus (beec h), Castanea (chestnut), Carya (hickory), Ulmus ( elm), Tilia(basswood or linden), Juglans (walnut), and Liquidamber (sweet gum). Different species of these genera occur on each continent.50 Figure 3-8: Temperate deciduous forest Growth forms Five layers are recognized:51  a tree stratum, 60 -100 feet high, dominated regionally by various combinations of the genera listed above;  a small tree or sapling layer, with not only younger specimens of the tall trees with species limited to this layer such as (in Virginia) Allegheny serviceberry or shadbush, sourwood, dogwood, and redbud;  a shrub layer often with members of the heath family such as rhododendron, azaleas, mountain laurel, and huckleberries;  an herb layer of perennial forbs that bloom primarily in early spring; and  a ground layer of lichens, club-mosses, and true mosses. Lichens and mosses also grow on the trunks of trees. 3.5.5. Mediterranean scrub These consist of shrubs and small trees with broad, hard, evergreen leaves called sclerophylls. Five areas occur worldwide on the southwestern coasts of continents in addition to the namesake area of the Mediterranean Basin.52 Figure 3-9: Mediterranean vegetation 49 Op. cit. (Terrestrial Biomes Of The World) (Temperate Broadleaf Deciduous Forest), Biomes of the World, Department of Geospatial Science, Radford University Ibid. (Temperate Broadleaf Deciduous Forest) 52 Op. cit. (Terrestrial Biomes Of The World) 50 51 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 34 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Vegetation Throughout the world, the Mediterranean biome is characterized by shrubs. In most regions these shrubs are evergreen and have small, leathery (sclerophyllous) leaves with thick cuticles. Sometimes the leaves are so reduced as to appear needle-like. Many typical members of the shrub flora are aromatic (for example, sage, rosemary, thyme, and oregano) and contain highly flammable oils.53 Mediterranean regions have long been impacted by humans especially through the use of fire and the grazing of livestock. The Mediterranean proper, we know from classical Greek literature, was formerly forested with live oaks, pines, cedars, wild carob and wild olive. 3.5.6. Temperate grasslands These are the typical vegetation of the interior of continents where they cover thousands of acres. Although grasses are the dominant life form, trees occur along streams in riparian woodlands.54 Vegetation Perennial grasses and perennial forbs [especially Compositae (or Asteraceae, depending on the taxonomic system used) and Leguminosae--the sunflower and pea families, respectively] are dominant growth forms. Two or more strata of grasses (erect grasses and recumbent species) are recognized in the more humid expressions of the biome.55 Figure 3-10: Temperate grasslands vegetation Grasses Perennial grasses, with their growth buds at or just below the surface, are welladapted to drought, fire, and cold. The tiller or narrow, upright stem reduces heat-gain in the hot summers; the intricate root systems trap moisture and nutrients. Two basic types are:56  Turf- or sod-forming grasses, with rhizomes or underground stems from which new plants spring forth; associated with the more humid grasslands  Bunch grasses, without rhizomes, that reproduce by seed; associated with the drier parts of the biome. 3.5.7. Desert scrub Warm deserts have hot summer temperatures with great diurnal temperature variations. Precipitation is slight and irregular. Shrubs, succulents, and annuals are common life forms in deserts worldwide. Productivity is low and limited by lack of moisture.57 53 (Mediterranean Scrub), Biomes of the World, Department of Geospatial Science, Radford University Op. cit. (Terrestrial Biomes Of The World) 55 (Temperate Grasslands), Biomes of the World, Department of Geospatial Science, Radford University 56 Ibid. (Temperate Grasslands) 57 Op. cit. (Terrestrial Biomes Of The World) 54 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 35 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Cold deserts are dominated by shrubs. The growing season is condensed between cold winters and dry summers. Polar deserts lie closer to the pole in the high arctic and are colder and drier than the surrounding tundra and have only scattered patches of vegetation in protected spots.58 Vegetation Shrubs are the dominant growth form of deserts. They may be evergreen or deciduous; typically have small leaves; and frequently have spines or thorns and/or aromatic oils. Shallow but extensive root systems procure rainwater from well beyond the canopy of the shrub whenever it does rain. These are the true xerophytes adapted to tolerate extreme drought. They form an Figure 3-11: Warm open canopy and, except after rains when annuals may cover the desert vegetation desert floor, the ground between shrubs is bare of vegetative growth.59 Water is not entirely lacking in the desert environment and several other growth forms represent strategies to reach water or to store water:60  Phreatophytes are plants with long taproots that may extend downward 20 to 30 feet to tap ground water supplies.  Succulents store water accumulated during rains for use during the intervening dry spells. Different species store water in different parts of the plant; hence we can recognize stem succulents, leaf succulents, root succulents, and fruit succulents. Most prominent among stem succulents are the Cactaceae. The agaves (Liliaceae) are examples of leaf succulents. Most succulents do not tolerate freezing temperatures so they are essentially limited to the hot deserts.  Another growth form adapted to desert conditions is the ephemeral. This is an especially short-lived annual forb that completes its life cycle in two-three weeks. The seeds are encased in a waterproof coating that prevents desiccation for years if necessary.  Perennial forbs with underground bulbs store nutrients and water in underground tissues and also remain dormant most of the year. They can sprout rapidly after sufficient rains and replenish their underground stores. 3.5.8. Tropical Savannas These are grasslands with scattered trees and with three growing seasons, warm and rainy, cool and dry, hot and dry. There is no cold season. They are highly productive and in Africa, for example, support large populations of grazing and browsing hoofed herbivores and large carnivores. Figure 3-12: Tropical Savannas vegetation 58 Ibid. (Terrestrial Biomes Of The World) (Desertscrub), Biomes of the World, Department of Geospatial Science, Radford University 60 Ibid. (Desertscrub) 59 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 36 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Vegetation Savannas are characterized by a continuous cover of perennial grasses, often 3 to 6 feet tall at maturity. They may or may not also have an open canopy of drought-resistant, fire-resistant, or browse-resistant trees, or they may have an open shrub layer. Distinction is made between tree or woodland savanna, park savanna, shrub savanna and grass savanna. Furthermore, savannas may be distinguished according to the dominant taxon in the tree layer: for example, palm savannas, pine savannas, and acacia savannas.61 61 (Tropical Savannas), Biomes of the World, Department of Geospatial Science, Radford University EMIL SHRESTHA; 66011, B. Arch. 066, V/I 37 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 4. Exhibitions Considerations 4.1. Introduction An exhibition is an organized presentation and display of a selection of items. In practice, exhibitions usually occur within exhibitory, galleries and exhibition halls.62 Exhibitions may be permanent displays or temporary, but in common usage, "exhibitions" are considered temporary and usually scheduled to open and close on specific dates. Interpretive exhibitions are exhibitions that require more contexts to explain the items being displayed. This is generally true of exhibitions devoted to scientific and historical themes, where text, dioramas, charts, maps and interactive displays may provide necessary explanation of background and concepts. Interpretive exhibitions generally require more text and more graphics than fine art exhibitions do.63 4.2. General design considerations 4.2.1. Planning and circulation Before considering the planning of the exhibitory it is essential to determine the size and location of the various services. Space allocations for subsidiary activities, or for those necessary to the functioning of the exhibition space in its relationship with the public (offices, rooms for meetings and lectures, library, documentation service) should be planned together Whereas, technical plant (heating and electrical apparatus, storerooms, workshops, garage, etc. .) can be housed in the basement or, if possible, in special outlying buildings to be built as annexes, at a convenient distance from the main building. The circulation of the space indicates the layout and direction of flow for visitors. This can be done by numbering objects, or the layout of displays. Circulation should feel natural and logical; the patron may feel herded and become resentful. Though a compulsory, one-way route may not be entirely desirable in a large exhibition space. Visitors should not have to turn back and return through rooms they have already seen, in order to reach the exit. They should, however, be able to turn off on their way round if they wish to cut short their visit or confine it to certain things that particularly interest them.64 Care should always be taken, however, to avoid the confusion of too many adjacent doors, or of rooms running parallel to one another; visitors must not be made to feel that they are in a maze where they can easily lose their way.65 Figure 4-1: Circulation diagram 62 (Exhibition), Wikipedia Ibid. (Exhibition) (CHIARA & CALLENDER, p. 333), Museums Cultural 65 Ibid. (CHIARA & CALLENDER) 63 64 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 38 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Density, clarity, and emphasis are other aspects to consider when planning a new space. Galleries and individual objects should be placed so that everything appears to have equal value and importance. Then within displays, objects should not be overcrowded or cluttered. 4.2.2. Entrance However many outside doors may be found necessary for the various exhibitory services (but these should be as few as possible, to facilitate supervision and security measures), there must be only one public entrance, placed quite separately from the others. This should lead into a vestibule where certain essential services will be located-sale of tickets, information service, and sale of catalogs and postcards. It should provide an easy introduction to the building, a point from which the individual visitor can find his way without difficulty and where large parties can be greeted and assembled. It must therefore be fairly spacious (one or two tables for the sale of tickets, catalogs, etc. ., a cloakroom, a few benches or chairs, a notice board, a general plan of the exhibitory to guide visitors, a clock). It is not advisable to have only one door from here into the exhibition rooms; there should be two, an entrance and an exit.66 4.2.3. Display Exhibits should be displayed in a way which allows the public to view them without any effort. This demands the variety of carefully selected, spacious arrangements. The normal human angle of vision starts from 27 degree up from eye level. For a standing viewer, this means that the exhibited object should be 10m away with the top not more than 4.90m above eye level and the bottom about 70cm below.67 Figure 4-2: Field of vision: height, distance Backgrounds must be subdued enough that they do not detract from the object on display, but they should be complimentary. The specific position, arrangement, and display of an object are important to consider. Label and explanatory accessories are essential to a patron‘s experience in an exhibitory. Enough information should be provided that the patron feels as if they understand what they are looking at. Some examples of these accessories are collection guides 66 67 ibid. (CHIARA & CALLENDER, p. 334) (Baiche & Walliman, p. 323) Museums and art galleries EMIL SHRESTHA; 66011, B. Arch. 066, V/I 39 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE available for the overall exhibitory experience, larger panels at the start of each gallery that can explain the intent of the collection, and smaller panels at each object should inform the viewer the object‘s use, medium, creator, and dates. 4.2.4. Lighting Lighting is extremely important and cannot be overlooked when planning new galleries. Natural light is ideal, but it must be filtered, and not too intense. It also should be consistent throughout the day – northern and southern exposure is ideal. Also, artificial lightings can be provided. But, the measures to mitigate the glaring effect should be taken care of. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 40 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 5. 5.1. The Eden Project Introduction The Eden Project is a visitor attraction in Cornwall in the United Kingdom. Inside the artificial biomes are plants that are collected from all around the world. The project is located in a reclaimed Kaolinite pit, Cornwall. The complex is dominated by two huge enclosures consisting of adjoining domes that house thousands of plant species and each enclosure emulates a natural biome. The domes consist of hundreds of hexagonal and pentagonal, inflated, plastic cells supported by steel frames. The first dome emulates a tropical environment and the second a Mediterranean environment. The project was conceived by Tim Smit and designed by architect Nicholas Grimshaw and engineering firm Anthony Hunt and Associates. The project took 2½ years to construct and opened to the public on 17 March 2001. 5.2. Figure 5-1: Aerial view of the Eden Project The biomes The Humid Tropics Biome, the most impressive section, is a multi-domed greenhouse that recreates the natural environment of a tropical rainforest. The warm, humid enclosure houses hundreds of trees and other plants from rainforests in South America, Africa, Asia and Australia. The dome is 787 feet (240 m) long, 180 ft. (55 m) high and measures 360 ft. (110 m) across at its widest point.68 From the Humid Tropics Biome, visitors move on to the Warm Temperate Biome. The Warm Temperate Biome, which has the same multi-domed structure as the Humid Tropics Biome, houses plants from temperate rainforests around the world.69 The Warm Temperate Biome at the Eden Project has varied plant life from temperate rainforests in Southern Africa, the Mediterranean and California. The final stop in the Eden Project is the Roofless Biome, an open area with varied plant life from the temperate Cornwall area, as well as similar climates in Chile, the Himalayas, Asia and Australia. Visitors can learn about plants that have played an important role in human history by following nature trails that wind over 30 acres (12 hectares) of land.70 68 (Harris), How the Eden Project Works Ibid. (Harris) 70 Ibid. (Harris) 69 EMIL SHRESTHA; 66011, B. Arch. 066, V/I 41 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE Figure 5-2: Schematic Master plan 5.3. Siting The Eden Project covers 15 hectares of land located in an old clay quarry 270 miles. The designers built the domes along the side of the pit that faces south, since the Sun is in the southern part of the sky in Cornwall. The slanted ground is perfectly positioned to absorb thermal energy all day long. 5.4. Structures The ETFE pillows are attached together to form geodesic domes. Many flat panels, formed into triangles, pentagons, hexagons or other polygons, are pieced together to form a curved surface. None of the individual pieces are curved at all, but they come together to form a rounded structure. Each pillow is attached to a web of interlocking steel tubes. Each dome actually has two web layers, one with hexagonal and pentagonal panels and one with triangular panels. The total Eden structure uses 625 hexagons, 16 pentagons and 190 triangles.71 71 Ibid. (Harris) EMIL SHRESTHA; 66011, B. Arch. 066, V/I 42 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE The steel frame of the geodesic dome is incredibly strong relative to its weight. This weight (667 tons) is dispersed evenly throughout the entire structure so that the dome only needs support around its base, leaving lots of room for the plants inside. The edges of the dome rest on a sturdy foundation necklace, an underground concrete wall around the perimeter of the structure.72 Figure 5-3: Steel tubes are used in geodesic dome 5.5. Figure 5-4: ETFE foils being installed in between the steel frames Coverings The ethyl tetra fluoro ethylene (ETFE) foil is used as a glazing material in the domes. ETFE foil is a perfect covering for a greenhouse because it is strong, transparent and lightweight. A piece of ETFE weighs less than 1 percent of a piece of glass with the same volume. It is also a better insulator than glass, and it is much more resistant to the weathering effects of sunlight.73 Figure 5-5: The ETFE foil covering with The Eden Project designers formed this louvers vents framed by aluminum profiles ETFE material into extremely sturdy pillows, each made from three sheets of ETFE foil welded together along the sides, one on top of the other, with layers of air pumped in between them. The air layers provide increased insulation without decreasing the amount of sunlight that shines through. The coolest thing about these pillows is that they are adjustable: On a colder day, they can be pumped up with more air to provide better insulation; on a hotter day, they can be partially deflated to allow more cooling.74 5.6. Other features 5.6.1. Soil Nourishment Initially the pit was composed mostly of clay, which does not have the necessary nutrients to support extensive plant life. Before the crew could begin constructing the 72 73 74 Ibid. (Harris) Ibid. (Harris) Ibid. (Harris) EMIL SHRESTHA; 66011, B. Arch. 066, V/I 43 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE greenhouses, they had to build up a level of nutrient-rich soil. They produced the richer soil by mixing clay waste from the area with composted green waste. In all, the crew produced some 85,000 tons of revitalized soil, more than enough to support the biomes' varied plant life.75 5.6.2. Water management and irrigation The designers build a sump, a water-collecting pool under the rich soil. Then they laid a buried layer of matting to channel rain water and any runoff water into this sump. This water is pumped out of the sump up into Eden's structure, where it is used to irrigate the plants, as well as drive the building's plumbing. The sprinklers and misting systems are used for the irrigation purpose inside the biome. This system collects, on average, almost 6 gallons (22.71 L) of water every.76 The greenhouse ceilings also collect rainwater, sending it to the sprinklers that keep the air saturated. Figure 5-7: Misting system used for irrigation Figure 5-6: Narrow pathways with sprinklers attached 5.6.3. Circulation and viewing facilities Various pathways are provided inside the biomes for easy circulations. Primary pathways are wide enough to accommodate large crowds while narrow pathways leads to the denser tropical rainforests inside. These pathways are provided with signs and labels to guide the visitors. Also, pathways are planned to provide different visual perception of the enclosed ecosystem inside. Figure 5-8: Wide pathways inside 75 76 Figure 5-9: Overhead steel platform providing view of the inside Ibid. (Harris) Ibid. (Harris) EMIL SHRESTHA; 66011, B. Arch. 066, V/I 44 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 6. 6.1. National Botanical Garden, Godavari Introduction The National Botanical Garden spreads on the area of 82ha about 16km far from Kathmandu on the lapse of the subtropical broad-leaved forests of the Phulchowki hill. The garden features 18 different greenhouses. Among them, the Tropical house is the main housing tropical plants. Other includes alpine house which is malfunctioned in the current state, cactus house and different poly houses. 6.2. The Tropical House The Tropical house is one of the main attractions of the botanical garden. The greenhouse occupies approx. 1400 sq. ft. and height about 30ft. The greenhouse houses tropical plants with two ponds catering aquatic plants. Figure 6-1: The Tropical House from south Figure 6-2: : Inside the tropical house 6.2.1. Planning and Circulation The length of the structure is orientated east-west for maximum solar radiations. The structure is planned in a rectangular layout with round plantation areas in the middle. Though entrances are provided on all four sides, only the entrance of the south is opened. A narrow pathway of around 4ft. circumambulates the planted areas and the ponds. While plants are grown freely on the soil in the middle, plants are grown in baskets and Figure 6-3: Plan EMIL SHRESTHA; 66011, B. Arch. 066, V/I 45 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE displayed on benches on the sides. Figure 6-6: Elevations Figure 6-5: Ponds with pebbles pavements Figure 6-4: Use of steel portal frames 6.2.2. Structure and coverings The whole structure is supported by the steel portal frames. The portal frames are erected from the ground with foundations inside the ground. As a covering the curtain wall of glasses framed in iron profiles are used. These coverings are supported on a 9in. thick wall of about 3ft. height. On the roof, wire meshes are used to cover the glasses. However, due to poor maintenance the glasses are broken at some parts underneath the rusted wire meshes. Also, gutters are used to drain down the rain percolated on the roof. 6.2.3. Utilities Sprinklers are installed for irrigation but they don‘t work anymore. So, manual irrigation is to be depended upon. Mechanical fans are used for ventilation and provision for well-functioning natural vents lack. For the purpose of lighting, fluorescent tubes are hung Figure 6-7: Sprinklers installed for irrigation EMIL SHRESTHA; 66011, B. Arch. 066, V/I 46 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE which are also not in a working state. 6.3. Other glasshouses A typical glasshouse shown in the figures are used for cacti display and other small plant displays. These structures are either supported by steel tubes or brick masonry with wooden posts. In some of these structures glasses are used for coverings, while in some polycarbonate sheets are used. A narrow pathway of about 3ft. runs along the length of the structure with plants display on the both sides. These plants are grown in raised concrete slabs and some in buckets. Figure 6-8: Typical sections of the glasshouses Figure 6-9: Wooden post supported cacti greenhouses EMIL SHRESTHA; 66011, B. Arch. 066, V/I 47 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 7. 7.1. Comparative Analysis Siting Both the studied complexes are planned and orientated to obtain maximum solar radiation throughout the day. Also, the complexes are built in respect to feature easy drainage. 7.2. Structures and material technologies The Eden Project is fabricated with advanced engineering technologies. The biomes in the complexes are designed to house basically two different types of vegetation: the tropical rainforest and the Mediterranean scrubs. For this purpose the structures are built large enough to house the native plants of the geographical region. The largest biome scales 787 feet (240 m) long, 180 ft. (55 m) high. To achieve this large magnitude geodesic domes are used which eliminated the support systems from inside to hold the whole structure. Also, the use of ETFE foils has benefitted the light weight construction of the structure. The foil itself is a durable, strong and translucent material perfect to use as a covering. To provide the whole structure with thermally controlled environment, the sheets of ETFE foils are used with controllable air inflation between them. This technology has created a par excellence in the indoor thermal environment of the structure. Though, the advanced engineering technologies and materials have their own advantages, these questions the cost for their fabrication and need of specialized manpower for maintenance. Whereas, on the other hand the glasshouses in the National Botanical Garden are constructed in simpler form using simple techniques and locally available materials. The use of simple steel portal frames in the tropical house has its own limitation to the scale of the structure. Though, the glasses are cheap, its durability, strength and translucency due to algae formations on them are real challenges. In addition, to this the used of wire mesh for the protection of the glasses have created a doubt for the use of glass as a covering material due to its fragile character. Also, the steel profiles used are in the state of rust which demands regular anti-rust treatments. Hence, an improvisation in the structural technology and materials can provide more durability to the structure and well-functioning of the complexes. 7.3. Utilities and services In the Eden Project, the adjustable ETFE foils have facilitated the heating and cooling of the indoor environment. Also, the use of louvered vents has eased the natural ventilations inside. Likewise, misting systems are used for the irrigation purposes which also have helped to maintain the required humid environment inside. More to this, advance indoor environment monitoring devices supervised through computers have helped to create a desired environment to grow the plants. But, in the glasshouses in the botanical garden, all the utilities are manually controlled and featured. Despite, the installations of the sprinklers, which is now not functioning; pipelines are used for plants irrigation. Poor natural venting system and use of EMIL SHRESTHA; 66011, B. Arch. 066, V/I 48 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE two small mechanical fans in the tropical house are unable to filter the stuffed air inside. However, in other small greenhouses, the natural ventilation system serves well. Overall, the greenhouses in the garden are in poor management and seek for regular maintenance; new technologies can be intervened in the structures for better functioning. 7.4. Exhibition considerations The sophisticated planning and arrangements of different exhibitory elements in the Eden Project is able to serve well for the visitors. Various pathways with the considerations of the crowding are defined inside the biomes. Also, different viewings angles are featured in the biomes which easily can guide the visitors inside and have a well look on the displayed ecosystem. The use of labels, signs have eased the visits inside and also provide relevant information to the visitors. Altogether, the considerations made for the exhibitory purpose inside the biomes are beneficiary for the large scaled greenhouse structures. In the glasshouses of the botanical garden, the planning and circulation is not a major issue due to the small scale of the structures. The circulations are easy and simple which caters the plant displays in a very small space. More to this, a close look on the displayed plants is well featured in the small exhibitory spaces. Hence, the circulation pattern can be used for small display purposed greenhouses. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 49 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 8. 8.1. Recommendations Purpose To act a greenhouse as a well-functioning botanical exhibition space, first the purpose of display is to be defined. As, all the plant communities cannot thrive to exist in a common environmental conditions, various environments are to be created as per their local geographical characteristics. So, a particular vegetation type to be housed inside the structure is to be chosen to create the climatic condition inside the structure. 8.2. Siting All the greenhouse structures should orient towards the sun to obtain maximum solar radiation. Also, the siting should be done to cater the drainage management. 8.3. Structures and material technologies The scale of the structure is to be defined by the environment and the ecosystem to be housed inside the greenhouse. Plants of various geographical regions have their own physiology and other characteristics. However, the growth and development of the plants can be controlled to be feasibly housed inside the structure. Also, the number of species to be sheltered defines the scale of the structure. For small scaled structures, the height should not be less than 4m to avoid the chimney effect. The engineering technologies for the construction of the structure are defined by the scale of the structure. Geodesic domes, arched structures, portal frames and other structural possibilities can be explored as per the scale and the site feasibility of the structure. Steel are to be preferred for durability, strength and stability of the structure. For large and complicated structures advanced engineering guidance are to be seek of. Glass as a covering material should be replaced by other choices, due to its poor strength. Polycarbonate sheets and its other forms should be preferred with the consideration of structural technologies, durability and strength. The glazing should be translucent and should feature maximum penetration of solar radiation. If possible, coverings with better insulations should be adopted. Also, the venting provisions should be considered of while selecting the coverings and the structural techniques. 8.4. Utilities and services Various advanced computer controlled utilities and services should be adopted. This helps in easy supervision of the indoor environment and creates a required environment for the ecosystem inside. For, irrigation misting system is more beneficiary as it also maintains humidity and cools the temperature inside. However, for the dry and arid ecosystem inside it should be replaced by ground sprinklers. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 50 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE For, heating and cooling purpose air exchange method is more preferable. However, insulation techniques should be preferred to reduce the overhead cost for machines operations. Likewise, natural vents are to be preferred rather than fans. 8.5. Planning and circulations While planning the inside space, practical and logical circulation should be followed. The display plants should follow the continuous circulation. These exhibitory elements should have a label or small descriptive information. Before, entering the main exhibition space, a sign with general descriptions should be featured for the visitors. Also, provision for pathways should be provided avoiding the maze formations inside. Different angles of perception if provided can boost display purpose of the institution. EMIL SHRESTHA; 66011, B. Arch. 066, V/I 51 INTERVENTIONS IN GREENHOUSE FOR BOTANICAL EXHIBITION SPACE 9.                   Bibliography (n.d.). Retrieved March 2014, from Eden Project: http://www.edenproject.com/ Baiche, B., & Walliman, N. (n.d.). Ernst and Peter Neufert Architect's Data (Third ed.). Blackwell Science. Basic, Greenhouse. (n.d.). Retrieved February 2014, from Primary Industries Agriculture: http://www.dpsi.nsw.gov.au/agriculture/horticulture/greenhouse/structures/basics Bioshelter. (n.d.). Retrieved February 2014, from Wikipedia: http://en.wikipedia.org/wiki/Bioshelter Boreal Forest (Taiga). (n.d.). 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