2-for-1 Deal: A Greenhouse Garage

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Photo by Debo Powers
This uniquely designed building functions as a greenhouse during the growing season and as a garage during extremely cold Montana winters.

Before I retired, I spent 12 summer vacations building a cabin in a remote part of Montana that’s 35 miles off the electric grid. The cabin features large windows with mountain views, a woodstove, and solar panels with storage batteries. I needed to construct two more buildings to make my homestead complete — a garage to park my truck in during winter months, and a greenhouse to grow vegetables in during spring, summer, and fall. Because I had limited funds for these projects, I designed one multipurpose building to fit both needs.

I constructed the “greenhouse garage” using lumber that had been harvested from my neighbor’s land and cut using my neighbor’s sawmill. I hired three friends and worked with them to build the structure. My design includes two gravel paths in the interior of the building. When the structure is functioning as a greenhouse, the two gravel tracks serve as pathways between garden beds. When it’s acting as a garage, I use the tracks as parking pads. I filled the garden beds with about a foot of topsoil each and hauled in gravel for the paths.

To moderate the hot temperatures that can build up inside the greenhouse garage on long, sun-soaked summer days, a solar-powered fan comes on automatically when the temperature reaches 80 degrees Fahrenheit. I can also open windows on the west and east walls, and the greenhouse design incorporates vents along the bottom of the building to create air flow. In our northern area, the cool summer nights — which dip into the 40s and even 30s — can also cause a problem for plants, so I watch the thermometer and close up the greenhouse after the sun goes down to trap the heat for as long as possible. If I’m diligent about managing the greenhouse, the indeterminate tomatoes grow as high as the rafters by the end of August and bear a bounty of ripe, colorful fruits. At the end of each growing season, I clear out the plants and the greenhouse becomes a garage once more.

Debo Powers
Northwest Montanta