Published by City Farmer, Canada's Office of Urban Agriculture
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
Contact:
Albie Miles
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).
| Crop (all varieties) | Area planted (square ft) | Total yield (pounds) | Yield per 100 sq. ft (pounds) | Avg. U.S. ag. yield per 100 square ft* |
|---|---|---|---|---|
| grain corn | 400 | 57.0 | 14.2 | 11.3 |
| amaranth | 433 | 60.2 | 13.9 | not available |
| wheat | 400 | 32.2 | 8.1 | 3.7 |
| potatoes | 445 | 215 | 48.3 | 52.3 |
| dry beans | 215 | 21.2 | 9.8 | 2.7 |
| winter squash | 225 | 199 | 88 | no data |
| storage onions | 36 | 31.5 | 87.5 | 68.6 |
Table 2. Yields of fresh vegetables from nutrition garden project.
| Crop | Area planted (square feet) | Yield (cups) |
|---|---|---|
| chard | 21 | 161 |
| kale | 21 | 146 |
| collards | 10.5 | 158 |
| broccoli | 71.5 (total area for broccoli through cabbage) | 56 |
| carrots | . | 90 |
| beets | . | 79 |
| green | . | 33 bu.* |
| onions | . | . |
| bok choy | . | 19 |
| leeks | . | n/a |
| cabbage | . | n/a |
| *bunches of 6 onions | . | . |
By the end of October, the 300-square-foot area of overwintering crops planted in late summer began maturing to a harvestable stage. Crops include chard, kale, collards, broccoli, dicon, kohlrabi, leeks, garlic, green onions, beets, carrots, and turnips, which will continue to produce through the winter.
Work Requirements Varied through Season
Except for the first propagations in January, Miles did all the work himself. In the first few months he needed only about an hour a week for propagation and early sowings.
But the heavy work began with the planting in mid March. From then until June 10 he worked an average of five days a week, six or more hours a day, double-digging the beds, spreading compost, transplanting seedlings, and irrigating, cultivating, and weeding.
From mid-June through August, maintenance and irrigation kept him busy an average of four hours a day, twice a week. Then, once harvesting began on August 22, he was back to six-hour days, but still only two days a week. That included time to build compost piles, process the grains, and put in cover crops and winter crops.
The cover crops, which protect against erosion in the rainy season, loosen the soil, and contribute to compost in the spring, consisted of vetch, oats, and bell beans. Miles finished work on the garden in early November.
Variety Trials Reveal Trade-Offs
An important aspect of the project was to determine which varieties of some crops perform best in the local climate. The trials included four varieties of amaranth, two each of spring wheat and grain corn, and three of dry beans. The results are summarized in Table 3.
Table 3. Results from variety trials of corn, amaranth, dry beans, and spring wheat.| Crop | Variety | Grain weight (lbs./100 sq. ft) | Biomass for compost (lbs./100 sq. ft.) |
|---|---|---|---|
| Grain Corn | 'Northstein Dent' | 15.2 | 32.5 |
| . | 'VT Yellow Flint' | 12.8 | 29.3 |
| Amaranth | 'Golden' | 13.4 | 17.2 |
| . | 'Burgundy' | 15.6 | 9.3 |
| . | 'Bolivia 153' | 12.1 | 23.5 |
| . | 'K432' | 14.5 | 14.5 |
| Dry Beans | 'Jacob's Cattle' | 10.4 | n/a |
| . | 'Midnight Black Turtle Soup' | 8.8 | n/a |
| . | 'Agassiz Pinto' | 10.7 | n/a |
| Spring Wheat | 'Polk' | 7.5 | 19.2 |
| . | 'Bountiful Gardens' | 9.8 | 12.0 |
Amaranth was one of the season's best producers. Of the four varieties tested, 'Burgundy' gave the best yield of grain (15.6 pounds per 100 square feet), but the lowest yield of compostable biomass (9.3 pounds per 100 square feet, air dried weight). 'Bolivia 153', by comparison, gave only 20 percent less grain, but more than twice the biomass. This information will help Miles and the Center's Farm & Garden staff choose varieties in coming years, depending on whether more compost or more grain is needed. The trial of two spring wheat varieties also revealed a tradeoff, with 'Polk' producing more biomass but less grain than the Bountiful Gardens variety.
In the dry bean trials, both 'Jacob's Cattle' and 'Agassiz Pinto' produced a pound and a half more dry beans per hundred square feet than 'Midnight Black Turtle Soup'. And 'Nothstein Dent' proved the better variety of grain corn, yielding 20 percent more grain and 10 percent more biomass than 'Yellow Flint'.
Establishing Compost Needs
The garden plot Miles used had only been worked for several years, so some compost had to come from outside the growing area rather than being generated from crops grown on site. Miles applied 10 cubic feet of compost per 100-square-foot bed before the first planting. This is a particularly heavy rate, which is usually necessary in the first year of a garden managed with the French intensive technique.
Next year, the beds should require much less compost, but just how much less is one of the key questions determining the feasibility of a "closed system" garden (one which requires no additions from outside the beds to sustain the soil). Miles estimates that his cover crops and uneaten biomass will generate at best 40 cubic feet of finished compost by next spring, enough for 1.6 cubic feet per 100-square-foot bed.
Ecology Action reports that annual application of between 1.6 and 2.8 cubic feet of compost per 100 square feet is enough to maintain fertile soil, depending on how intensively the soil is used. But at the UCSC Farm & Garden, as well as at the Ecology Action gardens in Willits (northern California), "the recommended application rates of compost have been difficult to achieve from the same growing area," Miles says.
Although Miles did not recycle his own waste into the garden this year, he says a composting toilet would help maximize the return of nutrients to the soil, and may become part of the project in the future.
Diet Based on Garden's Bounty
From April to October, Miles's diet consisted almost entirely of food represented in the garden. In the case of the storable crops (like grains and dry beans) he purchased food that he would have had on hand if he had grown the garden the year before.
This vegan diet provided approximately 2,900 calories a day and all necessary nutrients with the exception of vitamin B12. For this vitamin, Miles supplemented his diet with nutritional yeast. A typical breakfast consisted of toasted amaranth porridge with winter squash. For lunch he ate stir-fried or steamed vegetables with wheat and amaranth chapati bread. Dinner varied a bit more, but often consisted of bean or vegetable soup and stir-fried potatoes and greens with corn tortillas or polenta (corn meal).
Future of the Garden
Although few people have the time or inclination to produce all their own food, even those who want only to supplement their diets from a garden can learn from the nutrition garden project. Miles recommends that if you can only choose a couple of crops to grow, dark green leafy vegetables and potatoes are good options. He says greens provide the most nutrients and potatoes the most calories, both for the smallest investment of time and space. These crops can also be among the most expensive to purchase when shopping for organic produce.
Miles will use much of the information he gained from the project to start an eight-session apprenticeship in small-scale intensive food production tailored for low-income, urban residents of Santa Cruz. His goal is to teach others the most time- and space-efficient means of producing a portion of their diet from an organic garden. Miles will also encourage apprentices to join or form food-buying co-ops for purchasing bulk items such as grains, which are less efficient to produce on a garden scale. He hopes to establish a model training program that can be replicated in any urban setting.
Next year, students in the Apprenticeship Program will continue the research Miles started. They'll test different crop varieties, try different composting rates, and experiment with diet, all with the goal of learning how to maximimize the nutritional output of a hand-worked piece of land on a sustainable basis.
References
Cleveland, David A. and Daniel Soleri. Food from Dryland Gardening: An Ecological, Nutritional, and Social Approach to Small-Scale Household Food Production. Tucson, AZ: The Center for Food, People and the Environment, 1991.
Duhon, David and Cindy Gebhard. One Circle: How to Grow a Complete Diet in Less Than 1,000 Square Feet. Willits, CA: Ecology Action of the Midpeninsula, 1984.*
Ecology Action's Comprehensive Definition of Sustainability. Ecology Action of the Midpeninsula.*
Jeavons, John. How to Grow More Vegetables (Fifth Edition). Berkeley: Ten Speed Press, 1995.
Jeavons, John and Carol Cox. Lazy Bed Gardening - The Quick and Dirty Guide. Berkeley: Ten Speed Press, 1993.
Melina, Vesanto, Brenda Davis and Victoria Harrison. Becoming Vegetarian. Summertown, TN: The Book Publishing Co., 1995.
Robertson, Laurel, Carol Flinders and Brian Ruppenthal. The New Laurel's Kitchen: A Handbook for Vegetarian Cookery and Nutrition. Berkeley: Tens Speed Press.
*For ordering information, call or write
Bountiful Gardens
18001 Shafer Ranch Road
Willits, CA 95490 USA
Phone: (707) 459-6410.
