ARTICLE ON GREENHOUSES AS A BUSINESS VENTURE
There are a Lot of articles out there about starting home businesses.
The following is the most thought provoking article I have come across re: Greenhouses.
ENJOY !
Greenhouses:
A business venture
American Vegetable Grower
Aug 2002 by O'Keeffe-Swank
The advantages of greenhouse production - growing in a controlled environment 365 days a year with more efficient applications of crop protection materials and improved product consistency - appeal to your entrepreneurial spirit. Now you're ready to do something about it: create a master plan.
"A comprehensive master plan is required to reflect how the owner intends the completed facility to look," says William J. Roberts, professor emeritus and retired director of the Center for Controlled-Environment Agriculture at Rutgers University. Roberts published a guide through Rutgers titled "Creating a Master Plan for Greenhouse Operations." His guide can also be found on the Web at aesop.rutgers.edu/-ccea.
Roberts says important components of a good master plan include a business plan, site evaluation, evaluation of the type of growing structures, equipment required, and the impact the expansion might have on the community at large.
The first step of a business plan is quite obvious, but it's also the most critical:
determining which crops to grow and the intended market destination. Investigating the market will identify the unmet needs and from there will help you choose the appropriate greenhouse structure and accessories for optimal yields, says Amit Zour, director of international sales and marketing for the Israeli-based Azrom Metal Industries.
For 20 years, Zour has helped growers from around the world find solutions for their greenhouse operations.
Site Evaluation And Future Expansion
Zour suggests collecting a list of local data to help determine the appropriate model, materials, and accessories needed for the greenhouse. Local information to collect includes:
* Soil and ground -
analysis of physical conditions and chemical composition.
* Climate conditions -
maximum, minimum, and average temperatures (day and night);
relative humidity (day and night);
wind velocity and direction;
radiation levels (hours and quantities);
annual rainfall;
quantity and loads of snowfall;
hail, and unusual natural phenomena.
* Topographic information -
appropriate planning for drainage, ground sloping, and directions of
planting as per radiation angles.
* Project site foundations -
water sources, electricity, phone lines and communication, and access roads.
In his guide, Roberts recommends putting all this information in a topographical map and says the elevations on the map should have one to two contour intervals. "Locations of streams, ponds, and dedicated wetlands are important for runoff considerations and the permitting process, if applicable," he adds.
Using this collection of local data, Zour says he shows growers the full picture by finding the cheapest option for the first investment and other options that could be more expensive but potentially yield better results. "Start as simple as possible, but as profitable as possible," he says.
Plan Ahead
Zour also considers future expansion in his assessment because planning ahead will avoid costly retrofits. "This is why one of the most important characteristics is for a greenhouse to be modular," he says. "If everything is considered from the beginning of the project, future expansion will just be a matter of buying more structure materials and other components. Everything should fit like a Lego."
Pertinent expansion needs to consider for the master plan include:
* Size of the greenhouse area.
Will you have enough space to expand?
* Water and electricity.
Will your sources handle the increased capacity?
Are you budgeting for increased usage?
* Packing house design.
Is it big enough to handle the extra load?
* Increased drainage.
How will you collect the drainage, and will you have to build a drainage canal?
Structure And Coverings
Determining the type of structure will depend on the growing system, level of automation, the crops to be grown, and overall physical arrangement on the potential site. Once the width of the greenhouse is determined, Zour recommends ensuring that the main poles are stationed every 13 feet to carry the pressure of the structure.
As Roberts points out in his guide, new environmental regulations limiting runoff from greenhouses make it beneficial to construct a solid concrete foundation. He suggests the walls extend below frostline and that they be 8 inches wide. Interior walkways should be 4 inches thick and at least 10 feet wide for vehicle travel.
Referring back to your local data, the structure should be designed to withstand wind gusts in accordance with local standards. The structure must be strong enough to support the load of plant foliage and internal service systems (such as trellising), and it should create minimum shading.
"Normally you'll have problems with shading in the greenhouse because the structure itself creates shade, and then some accessories add to the shade," Zour says. "Since a high percentage of light transmission is needed for photosynthesis, we have to get the maximum of natural light transmission via the different kinds of coverings."
Greenhouse Coverings
There are two families of greenhouse coverings. Hard coverings available include polycarbonate, glass, and in some cases, polyvinyl chloride. Soft coverings include polyethylene film and a combination of additives, such as ethylene vinyl acetate.
Polyethylene and glass block ultra-violet light (UV). Plants don't need the LTV spectrum of light (the group of wavelengths between 0 and 350 nanometers), but insects thrive on it. Plants are very limited on the amount of light they take in, Zour explains. So it's good to filter out what they don't need and to capture more of the spectrums of light needed for photosynthesis. Special glazings, or enhancements added to the covering materials, provide these advantages.
Aside from glazings that limit LTV, other enhancements include infrared radiation absorbency and anti-condensation drip surfaces, as well as unique radiation transmission properties.
Another desired property is a high rate of electricity to repel dust on the exterior of the greenhouse, Zour says. Dust creates more shade on the exterior, but coverings with the added electric properties will not allow the dust to cling.
Ventilation, Heating, Cooling & Accessories
Optimal temperatures for vegetable production vary according to crop, variety, and stage of development. But as a rule for tomatoes, Roberts' colleagues at Rutgers say temperatures are kept between 70 deg F to 80 deg F during the day and 60 deg F to 65 deg F at night.
As a side note, more complex temperature manipulation strategies can be used to further control plant growth.
Whatever the requirements may be, keeping the temperatures out of the danger zone requires proper ventilation, cooling, and heating of the interior.
Active Or Passive
There are two types of ventilation: natural (passive), and active (forced) with the use of electric fans. Natural ventilation requires the maximum amount of airflow in the greenhouse using sidewall curtains and roof vents. "We are creating a chimney effect," Zour says. "We give the air enough space to enter through the sides, and then enough space to escape through the roof vents."
Active ventilation requires more accessories and is more expensive. But an added benefit to using active ventilation is creating an evaporative cooling system with the wet pad and electric fan combination, Zour says. This is done by placing an electric fan on the interior of one side of the structure and a wet pad on the opposite exterior wall, which sucks cooler air through the greenhouse.
Since greenhouse models vary around the world according to climate, so too will the HVAC - heating, ventilating, and airconditioning - and other accessories.
In Northern U.S. regions, greenhouses typically require high-tech operations due to extreme temperatures in both winter and summer, Zour says. Good heating systems, mostly using hot water, are needed in the winter, while the pad and fan combination is a typical cooling solution for the summer, he adds.
The Southwest region of the U.S., with its warm and dry climate, makes it more feasible for growers to rely on structures that take advantage of natural ventilation.
With Florida's warm and humid climate, ventilation is key, Zour says. Models are built to use natural ventilation, and with circulation fans, reduce humidity.
"A thermal screen that doubles for summer shading could be one of the best investments a grower can make," Roberts says.
He also refers to proper heating for optimal yield. Before a transportable bench system is considered, there has to be an excellent environmental control system installed. "If you're spending the money, do the environmental control system first," says Roberts. This will ensure uniform growth for easy handling.
Irrigation Growing Media & Temperature Controls
One major benefit of greenhouse production is the ability to control growing conditions around the root system, including irrigation and
nutrition, and with soilless cultures to maintain aerated surroundings.
Irrigation systems vary in design and layout. If automation is a priority, a greenhouse design should allow for future installations of automatic control and equipment, Roberts says. Also, ensure the fertilizer injection system is compatible with the installed irrigation system.
There are several options for growing media. Aside from deciding whether to use local or imported soil, substrates (or soilless beds) are another option from which you could choose rockwool, perlite, coconut fibers, sawdust, or volcanic cinder. Another option is Nutrient Film Technique (NFT), a hydroponic system that allows for even better root control.
Quality analog and computer systems are available to accurately sense and control both aerial and soil temperatures, Roberts says. Computer systems can record data for subsequent use in evaluating plant performance or identifying problems with the growing system.
The list of greenhouse technologies that you can add to your master plan seems endless, but as Zour suggests, keep it simple at the beginning of the project and plan ahead to add more later.
Hope your Holidays are going well...
`Greenjeans
it's not easy being green...
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posted by Greenjeans @ 6:23 PM
