By Marion Good and Martha Davis
March 2010
Ever since Gary Paul Nabhan (Coming Home to Eat) and Barbara Kingsolver (Animal, Vegetable, Miracle) urged their readers to help the planet by buying food grown within 250 miles of home, many of us have been trying to notice where our food is grown. A while ago, Wendell Berry proposed the idea that everyone should have a garden for food. But here on our high-desert mesa in Los Alamos, with little water and lousy soil, these ideas seem impossible.
Yet a recent visit to various Colorado and Wyoming greenhouses proved that in fact food can be grown all year round. We began with a hair-raising trip up Basalt Mountain in ice, mud, and snow to meet Jerome Osentowski. There at 7300 feet he grows food plants including tropicals through all the seasons. His secrets? Sun exposure, insulation and thermal mass. His greenhouse has a long south-facing side glazed with triple wall polycarbonate (which is somewhat insulating). There is vertical insulation between the soil and the foundation. The north wall, north-facing roof, all of the west wall, and part of the east wall are all insulated. The thermal mass is in the form of the soil in the greenhouse. There is air-filled 4" piping 3-6 feet deep under the whole greenhouse. Hot air from the top of the greenhouse is pushed by a fan through the pipes. As the air warms the soil, the air itself cools. On the day we were there the temperature difference between the inlet and outlet air temperatures was around 30 degrees. At night when the greenhouse air is cool, the thermostatically controlled fan comes on again to push relatively warm air from the soil into the greenhouse. It was an awesome experience to sit inside the greenhouse enjoying the warmth and tropical ambiance while outside was ice and snow.
The next stop was the Cheyenne Botanical Garden where the same basic principles are being used. That greenhouse uses thermal mass in the form of a series of 55-gallon drums painted black and filled with water. The whole of the north side was covered with drums stacked 3 deep on edge, on the order of 3-5 gallons per square foot of glazing. It was wonderful to see so many plants in bloom and vegetables ready to harvest in late February; they had cabbages, lettuce, and arugula, with tomatoes and bananas to come later.
In addition, we visited a couple of homes where the thermal mass was provided by one-gallon milk jugs filled with water and dark-painted cattle drinking troughs. But whether you use the thrifty approach and scavenge your materials from the dump or hire a professional builder to construct your greenhouse, the fact is that food can be grown year round. Tomatoes and peppers were in bloom; salad greens were in profusion. We saw figs, guavas, yacon, passion fruit vines and bananas.
The Cheyenne greenhouse belongs to the city and is mostly run by volunteer labor in return for produce. In Colorado and many other states, high schools are building solar greenhouses and teaching children to grow food as part of their curriculum. PEEC's summer gardening class has succeeded in engaging kids in the fun of watching the seeds they plant turn into the makings of dinner - the kids have planted a soup garden, a pizza garden, and more. But now we'd like to gear up for year-round food and some native plants.
After seeing these remarkable projects, we might now be prepared to answer the question of whether we could increase our food security and grow some of our own food with a resounding YES. Forget limiting yourself to a 250-mile range - try limiting yourself to your own backyard. PEEC is planning to convert our greenhouse to a thermal mass demonstration project. We'd like to hear from others in Los Alamos who have tried similar ideas. Please contact us at PEEC (662-0460) or send us an e-mail to Center@PajaritoEEC.org and we'll respond to your ideas.
Marion Good has recently moved to Los Alamos after living in Columbus, New Mexico, and several African and European trouble spots. With other PEEC gardeners, she is showing how gardens can be both beautiful and useful. She will be teaching kids' gardening this summer.
Martha Davis is contemplating a greenhouse for her yard. She teaches about gardening and the interactions between food, genetics, ecology, and gardens at PEEC after many years teaching at Botanic gardens and the Morton Arboretum.
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