What if you could grow fresh vegetables year-round without heaters or grow lights?
What if your rainbow of crops included everything from kale to radishes to spinach?
What if you could grow them even in the snowy, bone-chilling winters of Maine?
Organic farmer Eliot Coleman is doing just that. His pioneering methods for year-round vegetable growing include cold houses, cold frames and row covers, and succession planting.
Not all foods can be grown this way; tomatoes and bell peppers will always be summer-loving crops that need heaters and grow lights to survive the cold. But all kinds of cooler-weather crops can be cultivated in the winter: arugula, beet greens, broccoli raab, carrots, chard, kale, kohlrabi, leeks, radishes, spinach, turnips, and more.
These crops actually “reach a higher level of perfection without the heat stress of summer,”i says Coleman. The rich flavors and luminous colors of his winter crops have made Coleman famous, as have his remarkably simple farming methods, which employ only the most basic materials and technologies.
Eliot Coleman’s farming adventure began in 1968 when he purchased 60 acres of land in rural Maine from Scott and Helen Nearing, advocates of sustainable living and farming. “The inspiration came from [the Nearings’] garden,” Coleman says. “They were producing many crops beyond the typical growing season in the protection of a simple, lean-to greenhouse built into a stone wall.”ii Coleman began teaching himself organic farming methods, and from 1974 to 1996 he visited Europe four times to convene with year-round farmers there and learn their methods.
Coleman now owns and operates Four Season Farm in Harborside, Maine, where he cultivates and sells vegetables all year and teaches apprentices and employees to do the same. “Our farm in Maine is both traditional and nontraditional,” writes Coleman in his book The Winter Harvest Handbook.
“We are traditional during the ‘growing season’—the summer months—when we produce fresh vegetables for sale. But we also produce fresh vegetables for sale during the winter moths—the ‘back side of the calendar,’ so to speak.”iii
“We avoid the word ‘greenhouse’ since many people assume that a greenhouse, if unheated, is a super-insulated technological marvel or a complicated heat-storage device. Ours is neither.”iv
Coleman’s cold houses, as they are called, are as spartan as they come: translucent plastic is stretched over simple pipe frames to form hoop-shaped shelters. Just as vegetables can survive the winter under an insulating blanket of snow, the microclimate created by the hoop house is enough to insulate crops and help them survive. Though the temperature inside occasionally drops below freezing, it’s still warm enough for the plants to thrive.
Cold Frames and Row Covers
Coleman’s first cold frames followed traditional design: he attached 30 by 60 inch glass panes in wooden frames to bottomless boxes made of 2 inch-thick planks. Though simple to build, the frames made a profound difference: crops inside didn’t freeze until outside temperatures dropped below 25° F. “Growing plants in a cold frame is the equivalent of moving them to a climate one and one-half USDA zones warmer, or about 500 miles to the south here on the East Coast,”v Coleman says. Cold frames also increase the humidity inside, further protecting plants from freezing damage.
In 1980 Coleman began using cold frames inside his cold houses for even better insulation from the cold. But when started growing crops commercially, Coleman had to replace the glass pane cold frames with something more cost-effective.vi
The result? Plastic row covers: translucent plastic sheeting supported by flat-topped wire wickets 12 inches tall, spaced every 4 feet.
Today these economical covers provide Four Season Farm crops the same double protection from the cold that traditional cold frames do, for a fraction of the cost. Coleman’s Maine farm falls in USDA zone 5, but inside his cold houses, under the row covers, the climate is zone 8.vii
All plants significantly slow their growth in winter because of the shortened day length. In order for winter harvesting to work, plants must be in the ground by late summer so that they are nearly mature by the time the days length is less than ten hours.viii
Sowing times for each crop are very specific. Each vegetable is planted more than once during a season so that all winter long there will be continual harvesting; this is known as succession planting. Coleman provides detailed information on sowing and harvesting dates for various crops in each of his books.
Eliot Coleman’s methods can be used to grow fresh vegetables year-round with minimal energy output, or no energy output at all. Once the basic materials for cold houses and row covers are purchased, expenditures are finished. You won’t run up your power bill with growing lights, fans, or heaters; you won’t have to purchase any expensive equipment, either.
For a small investment you can grow crisp, enticing vegetables for your family all winter long. Those interested in Coleman’s methods should consult his books: The Winter Harvest Handbook, Four-Season Harvest, and The New Organic Grower.
“Instead of bemoaning the forces of winter and trying to fight them by adding heat, we have limited our intervention to the climatic protection provided by one or two translucent layers,” Coleman says. “Instead of trying to grow heat-loving crops during cold weather, we have said, ‘So it’s cold, great! What likes cold?’ The answer is some thirty or more hardy vegetables.”ix
Coleman, Eliot. Four-Season Harvest. White River Junction, Vermont: Chelsea Green Publishing, 1999, 1992.
Coleman, Eliot. The New Organic Grower. White River Junction, Vermont: Chelsea Green Publishing, 1995.
Coleman, Eliot. The Winter Harvest Handbook. White River Junction, Vermont: Chelsea Green Publishing, 2009.
i Coleman, The Winter Harvest Handbook, 4
ii Coleman, Four-Season Harvest, xv
iii Coleman, The Winter Harvest Handbook, introduction
iv Coleman, Four-Season Harvest, 4
v Coleman, The Winter Harvest Handbook, 27
vi Coleman, The Winter Harvest Handbook, 29
vii Coleman. The Winter Harvest Handbook, 56
viii Coleman, The Winter Harvest Handbook, 8
ix Coleman, Four-Season Harvest, 4-5