Solar greenhouses are a great way to save energy. Eco-friendly, energy conscious and money saving, a solar greenhouse is easy to obtain with a few upgrades and a little effort.
 
There are two types of solar greenhouse set-ups: active and passive.
 
Passive Solar Greenhouse

A passive solar greenhouse is the easiest, and generally the most inexpensive type of solar system to obtain and install. Passive solar systems collect heat from the sun during the day and store it for release during the night. This system often replaces the need for supplemental heating systems on all but the coldest of nights in most climates.
 
In order for a passive solar greenhouse to be effective, the greenhouse must have a glazing material that allows the passage of light, while retaining heat. Insulation is also generally used in areas of the greenhouse that receive little sunlight, and a storage medium in necessary. The easiest storage medium is water.
 
Drums of water placed under gardening benches and positioned to come into contact with sunlight streaming in through the sunniest areas of the greenhouse will provide sufficient heating for the entire greenhouse. A general rule of thumb for how much water is needed is 2 -5 gallons of water for each square foot of glazing (corrugated plastic, doubled walled glass, or polycarbonate film), depending on your regional location.
 
Active Solar Greenhouse

The active solar greenhouse system most often uses water as a storage medium but it also may incorporate a pump for circulating the heating water or solar energy panels to supplement the natural radiation of heat from the medium during cooler periods.
 
In an active solar greenhouse, water storage pipes are often placed below ground level in the greenhouse to take advantage of the natural thermal heating and cooling properties of the soil. In this system, corrugated tubing is used and the tubing system size is equal to the surface area of the greenhouse floor.

Solar greenhouse systems are energy efficient, economical, and easy to maintain. For greenhouse gardeners, the sun is a friendly source of heat, light, nurturing, and enjoyment.

**If you would like more detailed information on solar greenhouse systems, the National Sustainable Agriculture Resources Center has more information on solar greenhouse systems at: http://attra.ncat.org/attra-pub/solar-gh.html.