Mother’s Solar Greenhouse

By The Mother Earth News Editors
Published on November 1, 1979
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The finished solar greenhouse.
The finished solar greenhouse.
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Raising the greenhouse frame.
Raising the greenhouse frame.
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Digging the greenhouse foundation.
Digging the greenhouse foundation.

Right this chilly, finger-nipping moment, fresh lettuce leaves are luxuriating in warmth and plump red tomatoes are “a-poppin’ their seams”  in MOTHER EARTH NEWS’ all-new solar greenhouse!

You see, the folks at the Eco-Village were so excited about this magazine’s series of seminars that they could hardly wait to start some hands-on building and experimenting of their own. So, before the first session had even begun, MOTHER EARTH NEWS’ eager helpers “jumped into” one of our long-planned “on the property” projects: the construction and testing of a solar greenhouse.

The 12′ X 16′ “ray catcher” (which, like any other truly solar greenhouse, is designed to utilize sun-given warmth for its only source of heat) will serve both as a demonstration building to help spread the solar “word” and as an experimental station for conducting indoor plant-growing projects. The structure went up in three days, but our staff didn’t do the work all alone. Nope, Joe Costion, Buck Orndorff, and members of Wooster, Ohio’s Wayne County Community Action Commission (all of whom were referred to us by the folks at Solar Greenhouse Digest) provided much of the necessary brains and brawn.

The finished plant house–an all-out solar structure–has absolutely no backup heating system, so this year’s winter vegetable crop could conceivably get “bit off” by frost. But folks ’round here are betting that we’ll have a bumper hothouse crop instead, because even though the greenhouse may appear to be plain and simple, the building has been designed from the ground up to catch (and hold!) heat efficiently.

For one thing, both the greenhouse’s south-facing windows and its roof overhang are angled to admit as much solar radiation as possible on that “unsunniest” day of the year, December 21 (and to keep down the amount of sunlight admitted on June 21, the summer solstice). The radiant heat that is collected in our gardener’s dream house is pretty likely to stay there too, because the back, sides, and ceiling of the “plantitarium” are stuffed with R-19-value insulation while the layers of the building’s double-thick windows (consisting of a Lascolite brand fiberglass outer shell and an inner ultra violet-inhibitor-treated polyethylene film) are separated by an insulating air pocket.

Along with these heat-capturing attributes, the greenhouse also has a great deal of thermal mass. This heat-absorbing “bulk”–provided by our tilled planter boxes, the underlying gravel floor, and 10 water-filled 55-gallon barrels that have been painted black and stacked along the north wall–will store the building’s carefully gathered radiant heat during the day and (slowly) release that precious warmth at night.

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