The greenhouse was built by my husband and me, based on information I gathered from dozens of library books combined into one building. It is made of glass (old storm windows) and treated lumber. The slanted side on the south and the roof are covered with lexan, a non yellowing material that lets in more light than fiberglass, thus more heat in the winter. Lexan has a guarantee of 20 years, in comparison to fiberglass which becomes brittle and discolors very fast. The lumber used is treated, and the greenhouse itself is attached to the potting shed permanently. It is built like a pole barn, with the posts set 32" in the ground on sacrete 4" thick, poured in dry under and around the base of the posts.

The benches, pictured below, stand at a height comfortable for me to work at, with a second shelf below. Water runs underground to the greenhouse from a cistern that catches rain water off the roof of the house. The water hydrant, also pictured below, is perfectly safe to use in the winter because the water shuts off 3 foot underground and the upper faucet is drained each time the handle is turned off. Click for water hydrant details.

My cold greenhouse is unheated, yet can reach temperatures up to 126 degrees on a sunny day in January, thus needing to be ventilated rather than heated. The automatic ventilators and an exhaust fan set by a thermostat take care of excessive heat. The exhaust fan is an old furnace blower on the second floor of the attached potting shed, with a vent in the highest part of the greenhouse under the eave of the shed it is attached to. Of course, when the sun does not shine, other means of providing heat is necessary.

I start seeds in a heated propagation bench, which uses a soil warming cable buried under the seed starting mix. The 6'X 2'X 8" bench stands at a comfortable waist height. The soil stays 74 degrees with the thermostat controlled heating cable. A miniature hoop on the propagagion bench, looking much the same as the plastic hooped greenhouses seen in store parking lots in the spring, maintains the humidity and temperatures necessary for germination of the seeds. Automatic misters are used as ecessary when the greenhouse is unable to be attended to for any length of time. Click for Propagation Bench Details

By March 15th, the seedlings have grown to the point they must be removed and potted. At this point, I have a thermostatically controlled electric heater kept set at 40 degrees just in case the temperature drops below 40 inside the greenhouse itself, so nothing will be lost. (This 220 volt forced air heavy duty electric heater with built-in thermostat could be used in the winter if I wanted to heat the entire greenhouse year around.) Inside the potting shed where the garden tools and extra supplies are kept, is a separate room for my chickens, and my guinea fowl who free range during the day keeping my gardens bug free, thus the gardeners for my yard once the plants are set out on May 15th, the predicted final frost date for my area. (ZONE 5)