By Francis Koster, Ed.D.
Roughly 15 percent of all fruits and vegetables consumed in the United States are imported from outside our borders. This creates both a cash drain to local economies and a potentially dangerous way for bad guys to put disease into our food supply. Another very large chunk of our food supply travels thousands of miles from elsewhere in the country at great use of imported oil, thus making us doubly at risk — an oil supply interruption could not only make gasoline scarce, it could also impact food availability, particularly healthy vegetables.
Local farmers who grow only during the traditional warm months also have a tendency to lose their market on the “back side” of the growing season when relationships with customers are severed for months at a time. During times when vegetable farms are not in full production, farm crews can find themselves unemployed — and often receive taxpayer support. So if we could find a way to produce vegetables locally 12 months a year, we have the ingredients of a change that can make our nation more food secure, provide more local employment, reduce taxes, increase the public health and shield food costs from rising fuel costs.
A problem with widespread adoption of this concept is that people have an outdated notion that one cannot grow vegetables economically year around. This is no longer true.
I asked my friend and colleague Jon Kennedy to help me research solutions to this problem so we could prepare an article for the www.OptimisticFuturist.org website. We found that Eliot Coleman has been perfecting the process of raising vegetables 12 months a year without heated greenhouses in Maine, of all places, for several decades.
According to Coleman, when it comes to winter gardening there are several misconceptions. For instance, not all crops need summer-like temperatures to thrive. While tomatoes may prefer higher heat, some vegetables like spinach and lettuce produce exceptionally well during the cooler seasons. Another common misbelief is that hours of sunlight are too short to allow growth. Coleman teaches us that it is not the total hours of sunlight per day that matters as much as the total number of hours of daylight from planting until harvest. During shorter periods of sunlight, crops do take longer to mature but proper planning across a wide range of dates can compensate for this extra time, allowing a 12-month harvest.
His farm sticks to three main principles to guide its operating philosophy: simplicity, low external inputs (including energy) and high quality outputs. By making the most effective use of this operating basis, Mr. Coleman has succeeded in creating an effective system during a season when plants are usually dormant. The simplest technology is used to generate an effective economy of scale that lengthens fresh vegetable crops through winter months, while providing local 12-month employment.
The main objective is to harvest at least three crops per year from every square foot of the cold houses; two harvests in the long Maine winter and at least one in the summer. To increase the farm’s effectiveness during these unforgiving winter months, he strives to pick vegetables that have the greatest tolerance to cold temperatures, adheres to a strict schedule for planting and harvest and ensures vegetables are under constant cover when cold weather dictates.
Surprisingly, the vast majority of the vegetables Coleman produces during the winter are grown in the cold houses that use no supplemental heat.
During winter production, the farm sets a target of $5 saleable product per square foot for its 12,000 square feet of available greenhouse space. The cool house target is $10 saleable product per square foot. (By comparison, large, heated commercial flower-growing greenhouses yield about $15 per square foot but have much higher energy costs.) The unheated greenhouses produce three crops per year. Being slightly warmer, cool houses can accommodate six crops per year. This detailed tracking system allows the farm to determine which vegetables return the greatest economic value. Combining the field and greenhouse crops, the gross income is $80,000 per acre per year.
The findings have been documented in Coleman’s books, which include “The New Organic Grower,” “Four Season Harvest” and “The Winter Harvest Handbook.”
As winter producing farms become more prevalent, national security increases, local jobs are created, taxes can go down, and money that used to go out of the local area to pay for food and fuel remains in the local community.
In these complicated times, it is easy to slip into a sense of hopelessness. Don’t. Instead, help put some of these ideas in your own community — for your sake, your children’s sake, and for our country’s sake. Working together, and imitating the success others have demonstrated, we can fix our current situation.
Copyright 2011. All rights reserved.