A Do-It-Yourself Greenhouse Shade Cloth

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PHOTO: MOTHER EARTH NEWS STAFF
With their homemade shade cloth, the author and her husband lowered the temperature in their greenhouse by 20°F in less than an hour.

A year ago last February, when my husband and I began the construction of our attached solar greenhouse, we looked upon our future structure as a means of helping us heat our old Missouri farmhouse and as a permanent home for my numerous houseplants. We never suspected at the time that, come summer, it would turn into an attached solar oven! When it did, we tried every means of temperature control we could think of, until we finally hit upon making a greenhouse shade cloth.

During the winter, we sent off for the 12-mil woven polyethylene we needed to make the walls of our solar structure. When the package arrived, we found in it a note from the distributor that warned us to be careful to vent our greenhouse properly, so that the space wouldn’t overheat during the summer months, shortening both the life of the poly and of whatever plants were inside.

Heeding this good advice, we installed a high vent on the west side and a low one on the east, so our region’s prevailing easterly winds would blow cool air in and hot air out. We also added a sliding glass door, and installed a wind-driven turbo vent (which my daughters gave me for Mother’s Day) in the roof. With all these precautions taken, my husband and I felt that surely our greenhouse was ready for summer. And, since we’d completed the whole project in early spring (while the weather was still chilly), we had a chance to sit back and enjoy the heating benefits of our sun room. Indeed, the addition did help our house stay comfortably cozy, and my plants thrived in the sunlight that flooded in.

Attempts at Greenhouse Temperature Control 

However, as summer approached and the temperature outside began to rise, the thermometer reading inside our greenhouse started to soar. When it reached a sticky 100°F (before mid-June!), we knew we had a problem, and that we’d better do something about our overheating system quickly, before summer really arrived!

  • Published on Jul 1, 1983
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