Building a Passive Solar Greenhouse
Aren’t all greenhouse’s solar? Yes, but a Passive Solar Greenhouse does not use an artificial heat source such as propane but rather utilizes the sun to heat water, concrete, or some other heat holding material.
This simple inexpensive structure is energy efficient and heated only by the sun. For more than ten winters, it has proven to be an ideal winter sanctuary for growing nearly any cool-season crop imaginable, including salad greens, broccoli and spinach. The Southwest Center's solar-heated greenhouse is situated on the top of a windy, exposed hill in southwest Missouri, the logic being that if it will work at this challenging site, it should work almost anywhere in reasonably mild, temperate climates. In keeping with the theme of simplicity these cool-season crops were grown with no supplemental heat or light to determine how they would fare. Crops were usually direct-seeded into the raised beds in early November, with some fast-growing crops such as lettuce being successively seeded throughout the season. Of course, plants raised elsewhere could easily be transplanted into the greenhouse in November providing a substantial jumpstart on the season. Usually by the first of April the greenhouse becomes too warm and is shut down for the summer.
Construction drawings and materials list available: Click here