by Kim Dieter

Created on: April 09, 2010   Last Updated: April 10, 2010

Greenhouses provide many advantages to gardeners.  They extend the growing season, provide a suitable environment to over winter plants and are an ideal location to start seeds.  Greenhouses can be as simple as a plastic cover over PVC pipe or freestanding structures designed to last for years.  There are several important considerations when selecting a greenhouse for the backyard. 

Temporary or permanent:

Greenhouses are often most useful during the late winter and early spring months.  Seeds can be started earlier than if sowed directly into the garden.  Therefore, some gardeners prefer to install temporary greenhouses.  A PVC pipe frame covered with polyethylene can be easy installed and removed.  Permanent greenhouses allow year-round use. 

Location of the greenhouse:

Greenhouses can be freestanding structures or attached to an existing building.  The greenhouse must receive maximum sunlight and is best located on the south or southeast side of buildings or shade trees.  The north side of buildings or trees is the least desirable location for greenhouses.  At a minimum there should be full sun during the morning.  Careful consideration to the construction and location of the greenhouse is necessary for windy or snowy areas. 

 Building materials:

Greenhouses may be constructed from a variety of materials including wood, galvanized steel and aluminum.  They may be covered with glass, rigid fiberglass, double-wall plastic or polyethylene.  Some gardeners prefer to construct the greenhouse from scrap, low-cost or salvaged materials.  There are many do-it-yourself greenhouse kits on the market. Fully constructed greenhouses can be delivered to the site.

 Requirements for a greenhouse:

A greenhouse must provide a suitable environment for plants.  Therefore a source of heat, a ventilation system, and in some cases, a cooling system is required.  Plants have a preferred growing temperature.  Tomatoes, for example, are a popular plant to start in a greenhouse and later transplant to the outside garden.  Tomato seed germinates best at 70 to 80 degrees F.  Temperatures below 50 degrees or above 95 degrees are detrimental to the germinating seed and young plant.  Tomato plants grow best at about 65 degrees.  A greenhouse used to grow tomatoes should have sufficient heat and ventilation to maintain the desired temperatures.

There are a variety of greenhouse heaters.  Often exhaust fans with shutters provide the necessary ventilation.  In warm weather an evaporative cooling system or shade cloth may be required. Waterproof thermostats attached to the heating and cooling systems will assist in maintaining proper temperature. 

 Other greenhouse necessities:

A concrete or gravel floor will be beneficial in a greenhouse to reduce mud.  A source of electricity and water is necessary for a functioning greenhouse. Benches (tables) or shelves to hold the pots or flats must be installed.  A secure door is a must.  An automatic watering system will maintain the necessary soil moisture levels especially for germinating seeds and young plants and cuttings.

By considering the design, location, materials, and heating and cooling systems, a fully functioning backyard greenhouse will provide an ideal environment for gardening projects.

Reference:

 http://www.wvu.edu/~agexten/hortcult/greenhou/buildi ng.htm

Learn more about this author, Kim Dieter.
Click here to send this author comments or questions.