Your climate and crops grown will greatly determine the best design of your greenhouse to achieve optimum results.
What works in an area with prolonged winter with snow, low light and blizzard conditions will not be suited for areas with hot tropical temperatures and high light intensity. Deciding on the proper greenhouse design and environmental controls to overcome the climatic challenges your area poses will greatly determine the ability to realize your goals of maximum plant health and growth.
Generally, there are several major climate conditions that will need to be considered:
An arid desert conditions with extremely high temperatures coupled with low humidity, high winds and associate dust and sand create adverse challenges to achieving successful healthy plant growth. In these extreme conditions, a simple shade structure with insect screen sidewalls is the most practical choice. Due to high heat and low humidity, cooling is best realized by a simple mist or atomized fog system. Additionally, a thermostat or computerized controller can be used to operate circulation fans to further create a healthy environment for your plants.
A Mediterranean or sub-tropical region is typical of desert areas in the 30 – 35 degree latitude can experience colder air temperatures in the winter period….with quite hot temperatures and low rainfall during the summers. These conditions are best overcome with a greenhouse that can be heated at night in the winter but still maintain cool temperatures in the summer. Ideally suited to control year around optimum environment is these conditions will be a greenhouse structure with a ridge vent, an exhaust fan and evaporative cooling pad system, a shade system for the warmer period….as well as a heating system during the winter. This combination of environmental control systems helps to hold down condensation in the greenhouse and associated bacterial and fungal conditions by allowing the moist air to escape through the roof vents while the inside of the greenhouse is heated to further reduce moisture. This combination of environmental controls are effective when the outside temperatures at night cool down creating humid conditions inside the greenhouse.
A temperate climate is characterized by larger fluctuation in rainfall and temperatures with emphasis on adequate heating and insulation to off-set the lower outside winter conditions thus ensuring optimum plant health and growth. Greenhouses with full covered surface, roof and sidewall vent that allow expanded areas for ventilation. Additionally, if you are a commercial grower with a large greenhouse, a multi-functional computer controller is important to handle all environmental systems such as ventilation, fogging, shade & thermal screen, heating, mist irrigation, lighting, etc. A double layer of polyethylene film plastic or a rigid twin-wall polycarbonate will greatly reduce the expense of heating and afford optimum environmental control.
A Northern Tier – Cold Temperature Climates would be considered above 45 degree latitude experience climate variations in temperature and natural sunlight. Often the temperatures in the day can fall below 32 F with copious amount of snowfall and shortened days during the winter.
Greenhouse engineered to withstand the particular areas conditions must be carefully determined. Typically a rigid roof is utilized to shed snow loads that would otherwise collapse a film plastic covered structure. This type greenhouse often requires supplemental lighting and CO2 due to the structure being kept closed during the winter extreme cold conditions.
Gothic Arch Greenhouses Design Team