Cheyenne's Passive Solar Energy Community Greenhouse

Relying on a passive solar energy design, the community greenhouse a local citizen's group built in Cheyenne, Wyoming provides work opportunities and supplies fresh vegetables for hundreds of people daily.


| September/October 1981



071 passive solar energy community greenhouse 1 exterior

The passive solar energy design of Cheyenne's community greenhouse includes double glazing.


PHOTO: SCOTT KAUFFMAN

Nowadays, more and more folks are trying to achieve some independence by producing their own food, but doing so can be difficult for urban dwellers who don't have the land, time, or resources necessary to invest in full-scale gardening. The townspeople of Cheyenne, Wyoming have found one solution to that dilemma, however. Working together, they built—and now operate—a passive solar energy community greenhouse that makes fresh vegetables available to many residents of the city, with the emphasis on providing free produce to folks who otherwise couldn't afford to garden.

In 1976, Community Action of Laramie County (a citizens' group incorporated to administer antipoverty programs) established a grant for the construction of an experimental community hothouse. A training program for volunteer construction workers then got under way, and the actual building was started on a donated tract of land in the summer of 1977. Most of the materials used were either recycled scrap or donations to the cause, so the overall cost of the greenhouse turned out to be quite low for a project of that size. The original $42,700 grant given by CALC was supplemented by $13,000 from the Community Services Administration and $2,000 from the county government. The final price tag, then, came to $57,700, which is quite inexpensive for a structure that serves as a large-scale food-producing "factory"!

The Nuts and Bolts

Since the greenhouse supplies vegetables for a great many people, it may surprise you to know that the installation's passive solar heating system consists of nothing more than the building's south-facing glazing and a number of hand-operated vents. Thermal mass for the 5,000-square-foot structure is provided by two hundred 55-gallon drums that are filled with water and painted black. The double glazing is made up of a layer of Filon plastic on the outside and Monsanto 602 on the inside. The building's walls, ceiling, and floor are all insulated: Polyurethane foam was applied around the floors, and eight to ten inches of fiberglass batting elsewhere.

The setup appears to be working just fine, too. Shane Smith, a practicing horticulturist and director of the greenhouse, reports that the lowest temperature yet recorded inside the enclosure was 34°F (which did no damage to the cold-tolerant plants being grown at the time). He notes, "That low mark was registered after ten cloudy days, with wind gusts up to 50 MPH and an outside low of -15°F." Furthermore, the backup heat source—consisting of two homemade woodstoves—has never been used, even during the coldest Wyoming winter in 50 years!

The gardening procedures employed in the solar arboretum are as basic and natural as is the building's solar heating system. A composting bin at the back of the structure provides a ready source of nutritious mulch for the crops ...and only biological pest control is practiced. Permanent inhabitants of the mini-ecosystem include ladybugs, lacewing flies, chameleons, praying mantises, and fireflies. Three kinds of predator mites, and a species of wasp that reduces the population of white flies, also help keep destructive insects under control.

Willing Workers ... and Customers

Initially, the Cheyenne Community Solar Greenhouse was staffed solely by senior citizens who volunteered their labor in return for a share of the bounty produced by the facility. However, that work force has since been expanded to include volunteers of all ages (who are eager for the chance to pick up hands-on experience in gardening techniques), youthful offenders (they work off their court sentences by completing a variety of duties at the site), and handicapped individuals (who are able to combine job training and horticultural therapy).





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