Making More Food With Less
Erica Barnett
January 15, 2008 1:42 PM
"It takes about 15,000 to 30,000 square feet of land to feed one person the average U.S. diet. I've figured out how to get it down to 4,000 square feet. How? I focus on growing soil, not crops."
That's organic/sustainable gardening guru and soil expert John Jeavons, author of the book "How to Grow More Vegetables Than You Ever Thought Possible On Less Land Than You Can Imagine," talking to the San Francisco Chronicle a few years back (via Grist). Jeavons has spent the last 30 years touting small-scale, sustainable, organic farming--a method of closed-loop crop production he has dubbed "biointensive farming."
Basically, biointensive farming incorporates many of the same practices as biodynamics, and takes them a few steps further. In addition to double-digging (tilling beds to a depth of 24 inches for greater aeration), planting in space-saving hexagonal or triangular patterns, planting complementary crops in the same space, and composting, farmers or gardeners employing biointensive methods use higher-energy crops (such as root crops) to increase the amount of calories a small piece of land will produce, grow some crops for use exclusively as compost (such as rye and alfalfa), and practice strict crop rotation to preserve soil productivity, among other things.
Some of biointensive farming's practices strike me as impractical on both a small and a large scale--human-waste composting is never going to become all that popular, for example, and I can't see many people doing the kind of intensive calories-per-square-inch calculations Jeavons calls for. Still, the method has some major advantages over conventional farming--the largest and most obvious being, of course, that it allows farmers to produce far more food per acre. That's a huge boon for home gardeners, like me, with little farmable land but a strong desire to get off the factory food grid. And it has exciting implications for subsistence farmers in places where arable land is scarce and growing scarcer--places like Kenya, Mexico, and Argentina, where Jeavons' methods are being used by thousands of small-scale farmers.
Stretching the productivity of a small amount of space is one way to increase harvests. Stretching out the growing season is another. According to a recent article in the New York Times, "extreme season extension" is growing in popularity as demand for local food increases. Using unheated low metal hoop houses and double-row covers, some farmers in the northern United States have managed to extend the season for certain produce through the spring, making crops like spinach and herbs available locally year-round. Hoop houses, it turns out, are cheaper than greenhouses; doubly so since, as temporary structures, they aren't subject to property taxes. Another season extension technology is called a high tunnel, which can be large enough to accommodate a tractor. With the popularity of both methods increasing, we may soon see local, organic strawberries on store shelves--in January.
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