The Nutrition Garden Project
Originally published in The Cultivar (Winter, 1997 issue), Newsletter of the Center for Agroecology and Sustainable Food Systems at the University of California at Santa Cruz.
By Jonathan Knight
(C) Copyright 1997
2458 Empire Grade
Santa Cruz, CA 95060 USA
Phone: (408) 421-9755
This past spring (1996), Center volunteer and apprentice program graduate Albie Miles began growing all his own food. From planting the first seedlings to laying in the last cover crops, he kept careful records of what he grew, what he ate, his labor, and his yields. Between April and October, he restricted his diet almost entirely to food from his "nutrition garden," which is located on a portion of the raised-bed garden site at the Center's 25-acre UCSC (University of California, Santa Cruz) Farm.
The project's goal was to find out what it takes to grow a complete diet with organic gardening practices that maintain the soil's fertility year after year. Miles had to plant crops in proportions that provide balanced nutrients and sufficient calories. The crops also had to produce enough compostable biomass to eliminate the need for annual amendments from outside the garden.
Miles, in consultation with apprenticeship instructor John Farrell, sought answers to questions such as how much work is involved, what to grow, and what the diet is like. He also tested different varieties of corn, amaranth, wheat, and dry beans to see which performed the best under Central Coast conditions. The project did not include exhaustive soil analyses or carefully controlled experiments - Miles calls it "soft science at best." Rather, the project was an attempt to implement what others have recommended. "This is what people are going to encounter if they try growing all of their own food," he says.
The nutrition garden covered 4,500 square feet, including paths, propagation area and compost piles, and 2,500 square feet of French intensive bed space. The main calorie crops were grain corn, grain amaranth, spring wheat, potatoes, dry beans and winter squash. Miles also planted onions, sunflowers, an assortment of dark green leafy vegetables (chard, kale, collards, and broccoli), and successive sowings of carrots, beets, green onions, and bok choy.
In coming years the nutrition garden will yield valuable information on how much compost the soil needs annually to stay productive, and what the long-term average yields for each crop are. The project will be integrated into the six-month Apprenticeship in Ecological Horticulture, giving students a chance to experiment with ways to produce a balanced diet and compost ingredients from a hand-worked garden plot.
Maximimizing Production in a Limited Space
Ecology Action of the Midpeninsula, a non-profit agricultural research organization, has set forward some guidelines for growing a personal nutrition garden using Alan Chadwick's French intensive techniques (see References). This gardening style produces phenomenal yields in double-dug, raised beds amended with compost. In situations where the soil is lacking in certain nutrients, organic fertilizers such as bonemeal, cottonseed meal, or kelp sand may be used to restore nutrient balance, but the long-term goal of French intensive gardening is to use compost as the main soil amendment.
In French intensive gardening, seedlings are planted close together so that the leaves of the mature plants just touch, reducing moisture loss from the bed and forming a living mulch that keeps weeds down. This tight, or "intensive," spacing in rich soil generates yields as much as ten times higher than those produced by conventional agricultural practices.
Following Ecology Action's crop recommendations, Miles planted 2,500 square feet of beds worked with the French intensive technique, and ended up several months shy of a full year's supply of food. However, much of the shortfall was due to a low potato yield, one that was less than half of the UCSC Farm & Alan Chadwick Garden's average. Furthermore, yields may well improve after several years of heavy composting.
Table 1 lists yields for the storage crops (grain corn, amaranth, wheat, potatoes, dry beans, winter squash, and onions). Yields of leafy greens were measured in cups of steamed vegetables (Table 2). Altogether, 125 square feet of bed space produced 1.6 cups of steamed vegetables a day from April 10 to October 26. These results represent only a single season - subsequent cropping seasons will provide data that will be used to determine average yields.
Table 1. Yields of storage crops from nutrition garden project. *Data from Jeavons (1995).