greenhouse is a 16'X 20' lean-to attached to a small barn that serves
as both a potting shed and entrance to the chicken coop/guinea home. The
entrance to my greenhouse is off the inside of the potting shed so the
winter winds do not blow in or let the heat escape as much when the door
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.
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.
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)
loves a greenhouse too.
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Let's share ideas and connect with others who have the experience of gardening under glass.