What a Little Chicken Breath Can Do
EVEN
on a blustery zero-degree day, it's so warm -- 80 degrees -- in Anna
Edey's solar greenhouse on Martha's Vineyard in Massachsetts that the
vents are open. Let those blizzards with their raging winds pound the
four layers of plastic glazing outside. The greenhouse has survived
hurricanes. And every week, this 3,000-square-foot space produces 60
pounds of greens -- 25 varieties of leaf lettuce and 20 other greens and
herbs, like chicory, arugula, beet greens, sorrel, cilantro, dill and
parsley. Nasturtiums and borage bloom. Insects drink their nectar.
This winter greenhouse, which grosses $100,000 a year, is a Solviva greenhouse -- Ms. Edey's own invention. The name is her tribute to the good life that the sun can bring. The greenhouse runs without oil or gas. Its heat and electricity come from the sun -- and the body heat of 100 chickens.
"Each chicken puts out eight B.T.U.'s an hour per pound," Ms. Edey said, as the clucking of hens and the occasional crows of two roosters filtered through the north wall. Each hen, scratching about on the earth floor and laying eggs in coops next to the greenhouse wall (lined with 50-gallon bags of water that collect heat), saves the business about two and a half gallons of fuel oil a year. And don't forget the two roosters. Multiply the savings by 100, and you save about 250 gallons of oil a year.
This winter greenhouse, which grosses $100,000 a year, is a Solviva greenhouse -- Ms. Edey's own invention. The name is her tribute to the good life that the sun can bring. The greenhouse runs without oil or gas. Its heat and electricity come from the sun -- and the body heat of 100 chickens.
"Each chicken puts out eight B.T.U.'s an hour per pound," Ms. Edey said, as the clucking of hens and the occasional crows of two roosters filtered through the north wall. Each hen, scratching about on the earth floor and laying eggs in coops next to the greenhouse wall (lined with 50-gallon bags of water that collect heat), saves the business about two and a half gallons of fuel oil a year. And don't forget the two roosters. Multiply the savings by 100, and you save about 250 gallons of oil a year.
Not to mention the gold in chicken breath. Chicken breath?
"They're producing CO2 , which plants need because carbon is their basic building block," said Ms. Edey, a 53-year-old Swedish-born weaver who raises her own sheep for wool. "So if you add more CO2 , the plants will grow more." The carbon dioxide content in the greenhouse is about three or four times as high as in the air outside, she added.
"So even with shorter days in winter, the plants grow faster than outside in the summer garden," she said. Considering that many commercial growers use bottled carbon dioxide to bolster production in their greenhouses, chickens might become a hot commodity.
The chicken breath gets to the plants via a solar-powered fan that draws the air from the chicken coop into a series of perforated pipes that lie beneath the soil of the growing beds. The carbon dioxide then simply rises up through the soil particles and into the air of the greenhouse, where it is absorbed by the leaves.
On Tuesdays, Ms. Edey and a crew of three harvesters pick enough greens, leaf by leaf, for about 200 one-ounce salads a day. The combinations, complete with edible flowers like nasturtiums, red salvia and borage blossoms, which are electric blue and as sweet as honey (bees love them, too), are rinsed in a big tank in the middle of the greenhouse, dried and bagged, and then sold on the island or shipped to restaurants in Boston. The greens are grown without chemical fertilizers or pesticides. Compost and seaweed beef up the soil, and if the aphids and whiteflies get out of control, Ms. Edey just orders more ladybugs and parasitic wasps.
Meanwhile, there is no burning oil to pollute the atmosphere.
Ms. Edey learned about the body heat and carbon dioxide of animals from a newspaper article that her ex-mother-in-law had sent her about 10 years ago, when Ms. Edey was experimenting with growing plants in the solar house that she built in 1980. The article told of a nurseryman in Oregon who had traded his oil furnace for 450 rabbits, which saved him $750 a year. (The annual oil bill was $1,000; rabbit food cost $250.)
"They're producing CO2 , which plants need because carbon is their basic building block," said Ms. Edey, a 53-year-old Swedish-born weaver who raises her own sheep for wool. "So if you add more CO2 , the plants will grow more." The carbon dioxide content in the greenhouse is about three or four times as high as in the air outside, she added.
"So even with shorter days in winter, the plants grow faster than outside in the summer garden," she said. Considering that many commercial growers use bottled carbon dioxide to bolster production in their greenhouses, chickens might become a hot commodity.
The chicken breath gets to the plants via a solar-powered fan that draws the air from the chicken coop into a series of perforated pipes that lie beneath the soil of the growing beds. The carbon dioxide then simply rises up through the soil particles and into the air of the greenhouse, where it is absorbed by the leaves.
On Tuesdays, Ms. Edey and a crew of three harvesters pick enough greens, leaf by leaf, for about 200 one-ounce salads a day. The combinations, complete with edible flowers like nasturtiums, red salvia and borage blossoms, which are electric blue and as sweet as honey (bees love them, too), are rinsed in a big tank in the middle of the greenhouse, dried and bagged, and then sold on the island or shipped to restaurants in Boston. The greens are grown without chemical fertilizers or pesticides. Compost and seaweed beef up the soil, and if the aphids and whiteflies get out of control, Ms. Edey just orders more ladybugs and parasitic wasps.
Meanwhile, there is no burning oil to pollute the atmosphere.
Ms. Edey learned about the body heat and carbon dioxide of animals from a newspaper article that her ex-mother-in-law had sent her about 10 years ago, when Ms. Edey was experimenting with growing plants in the solar house that she built in 1980. The article told of a nurseryman in Oregon who had traded his oil furnace for 450 rabbits, which saved him $750 a year. (The annual oil bill was $1,000; rabbit food cost $250.)
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| www.solviva.com |
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