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5 Production Facilities
Greenhouse Technology (GHT100S)
Cape Peninsula University of Technology
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Production Facilities
- Design for use
a) Type of crop
The type of crop considered should be one of the primary criterions used to determine a suitable greenhouse design. Bedding plant facilities do not require as much “head room” for growing as would be required in a rose or carnation range. On the other hand, the type of automatic or mechanical requirements may dictate a similar design for growing all floriculture crops. The bedding or potplant grower may move all containers with a forklift, tractor or overhead tram. The carnation grower often leaves plants in production two or three years and constructs elevated walks. In some areas of the world it is not unusual to see potplants on two or three shelf levels in the greenhouse. Greenhouses used for vegetable production often incorporate tractors, planters, and harvesters into their program and the structures must be designed to meet these needs – head room in a plant growing facility must be considered.
If a grower anticipates definite crops, that would be comparable to a specific greenhouse design, then he would probably decrease the cost of his initial investment and no doubt lower his operating costs for years to come by purchasing a specific structure. Coupled with the “design for use” is the need to consider economics of heating and cooling efficiency, construction costs and durability.
b) Bench type
Several bedding and pot plant growers have eliminated benches in their production areas. One grower places his poinsettia crop on a concrete floor and follows it with bedding plants. Another covers the ground with gravel and has concrete walks – the bench has been completely eliminated. Many other wholesale bedding plant growers have also eliminated benches. Plant production at ground level could prove more costly for the grower due to temperature differentials which will be discussed later.
In recent years, many cut flower growers have started planting directly in ground beds. Wood can be installed around the perimeter to retain the growing media, for attachment of water systems and to act as a kick board to decrease the possibility of contamination from the walk areas.
Where subsoil conditions prevent good drainage, perforated tile and gravel can be installed in the bottom of a 600 or 750 mm trench, dug with a backhoe. The topsoil or modified mix is then placed on top of the gravel and the perimeter boards constructed.
Ground beds are often difficult to pasteurize or fumigate. Some growers inject steam through the tile, if it is clay or material that will withstand the temperature. Ground benches are basically elevated ground bed. A box or bench with side walls is constructed on piers. Many growers of cut flowers and vine crops prefer this type of
low growing area because potential disease, water and growing media problems are easier to control.
Elevated benches have been a tradition in design and only in the past decade have growers in the U.S. realized that certain types are uneconomical. If short species or single-crop types of cut flowers are grown in raised benches, then sound bench legs, bottoms, and sides will be necessary to withstand the maximum load. The concrete bench has proven satisfactory in many greenhouses. Many operators have designed their own benches and they have proven valuable. Table 1 describes six types of raised benches that can be constructed by the greenhouse operator. Almost any combination of material can be and is used.
TABLE 1: BASIC MATERIALS THAT CAN BE USED FOR GREENHOUSE BENCHES
BOTTOM LEGS SIDES
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Corrugated asbestos Pipe, concrete, Flat asbestos aluminium
Flat asbestos Pipe, concrete Flat asbestos aluminium
Wood Concrete block Wood
Welded wire Wood, concrete block none
Expanded metal Concrete block none
Concrete Concrete concrete
Bench arrangement and utilization can be the controlling factor on a profit and loss statement. A good manager will design benches to fill the greatest ground area as possible. Many greenhouse facilities are limited to two or three bench arrangements or combinations thereof. Greenhouse structures have been designed with a definite correlation between number of longitudinal benches that will fit into a facility, and the width of the structure. Most longitudinal and island benches have been traditionally designed, 1 m wide although some may be 1,2 – 1,5 m. The 1 m bench is more convenient for reaching plant materials in the center of the bench. Bedding and pot plants are often grown on peninsular benches which can be 1,5 – 1,8 m wide and still convenient. There is also a height of bench above ground versus width correlation for ease of handling plant materials.
The combination of tiered benches has been reintroduced in the past few years especially in the retail floricultural outlets for display purposes. ‘Due to lower light requirements of foliage plants, the tiered bench can provide an excellent gross return for the ground area covered. Benches tomorrow – Many growers and industry- related personnel have been considering bench designs for decades. The ideal
Mechanization
Every effort should be made to decrease overhead costs and the greenhouse operator must include as much mechanization as is economically possible into his plans, where designing any type of greenhouse facility. Most growers place mechanization as one of their top priority needs. Obtaining one new piece of equipment that can reduce overhead cost is not necessarily being mechanized, but it is a start. For the most part being mechanized means developing labour-saving systems that will reduce labour input and the number of times materials are handled. Mechanization can work bilaterally – take the components of a crop to the worker or take the employee to the crop. In Japan, a suspended rail system is being used to water, feed, and spray potplants spaced on the ground. The research station in Wageningen, Holland is conducting studies with totally movable pallets for potplants that cover an entire greenhouse. They have developed a machine that will “pot” plants and place them on a wire pallet. The pallet is suspended in a nutrient solution for a period of time. After growth is achieved, the pallet, mounted on rollers is pushed to the marketing area.
Plans for “shading” systems for photoperiod control should be included in all new greenhouse structures. Many systems are automated and cover thousands of square meters in minutes. The same system can be employed to develop a smaller volume for greenhouse cooling purposes by installing a clear plastic film. Equipment for mechanization systems is not necessarily greenhouse orientated. Many growers use ingenuity and adapt equipment from other industries to their system.
Support facilities
Support facilities in some instances are considered a luxury. But are necessary in order to obtain the greatest return from the production area and are required for efficient management.
Every greenhouse operation can use refrigeration facilities in many ways including bulb rooting, cold induction, cut flower storage, and for holding seedlings and potplants. Flammable and pesticide storage facilities must be created. Such facilities are required to be separated from other support or production areas. A third facility that is becoming a necessity is an employee lounge and lunch room.
The office area has become an important part of the greenhouse complex, especially for those operations that have environmental control panels and communication centres. The greenhouse of the future will not only be monitored for temperature, but some programs will utilize television cameras to monitor plant conditions, employee production and shipping and handling activities, all from the office.
SUPPORTIVE NURSERY STRUCTURES
In order for a nursery to work fluently, certain supportive structures are necessary.
- Fertilizer Store
Concrete and brick store.
Well ventilated, dry and cool (fans sometimes necessary).
Fertilizers in bags stored above floor level on wood. (Ventilation).
Mark fertilizers.
- Chemical (Poison) Store
2 Concrete and Brick Store Well ventilated, dry and cool (farm). Racks/Shelves for small quantities. Open space form drums. Storage for protective equipment and clothes. Warning signs.
2 Open space outside, connected to store Fence off. Taps and sinks (mixing, cleaning and treatment of seed and bulbs). Shelves of wire mesh for drying of plant material. Warning signs.
- Shadecloth House
3 Functions Expanding production area under favourable weather conditions (seedling, flower and asexual production). Hardening-off area. Storage of motherstock plants and container grown plants.
3 Construction Wood. Steel pipe/steel wire. Nylon cloth (Alnet). See lath house
3 Shading 30 – 75% reduced sunlight. Also has an affect on wind-reducing wind speed.
Cold room for flowers at ‘Oakvalley’ cut flower nursery
- SEED STORE Concrete and brick. Temp. and R. control/ventilation. No light. Racks for seed container storage. Tables for drying and cleaning of seed. Rodent proof!
Seed drying tables at Writtle Horticultural College (UK)
7. TOOLS AND EQUIPMENT STORE
Concrete and brick. Shelves for smaller tools. Shelves for spades, rake etc. Control area for storeman. Area for spare tools. Area for materials. Area for equipment. Service and repair area. Natural light (windows). Artificial light. Electricity plugs (services and repair area). Work bench and tools (in service and repair area).
Arrangement of bench tools and garden tools in a tool store
- LATH-HOUSE
8 Construction Wood. Aluminium/steel
(i) Support: Wood and pipe support set in concrete support cross-members.
(ii) Shade: 50% - laths (50 x 30 mm) spaced 50 mm apart.
(iii) “Shading with Water” Sprinklers to cool the plants on hot days.
5 Production Facilities
Course: Greenhouse Technology (GHT100S)
University: Cape Peninsula University of Technology
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