method is an organic agricultural system
which focuses on maximum yields
from the minimum area of land, while simultaneously improving the soil
. The goal of the method is long term sustainability
on a closed system
basis. It has also been used successfully on small scale commercial farms.
Many of the techniques that comprise the biointensive method were present in the agriculture of the ancient Chinese
, and of the Early Modern
period in Europe. Alan Chadwick
brought together the Biodynamic
and French intensive
methods, as well as his own unique approach, to form what he called the Biodynamic-French Intensive
method. The method was further developed by John Jeavons
and Ecology Action
into a sustainable 8-step food-raising method know as "GROW BIOINTENSIVE." The method now enjoys widespread practice and development. The Southside Community Land Trust
located in Providence, Rhode Island, uses the biointensive method to produce food on its city farm
. This technique is preferable because it yields large amounts of food for both local sale and donation.
In order to achieve greater productivity, the biointensive method uses double dug raised beds, intensive planting, and companion planting.
- In double digging, a 12 inch (305 mm) deep trench is dug across the width of the bed with a flat spade, and the soil from that first trench is set aside. The 12 inches (305 mm) below the trench are loosened with a spading fork. When the next trench is dug, that soil is dropped into the empty space of the first trench, and the lower layer is again loosened with a spading fork. This process is repeated along the full length of the bed. The final trench is filled with the soil that was removed from the first trench. The result is a bed that has been tilled to a depth of 24 inches (610 mm). When an entire bed has been double dug, the soil will have greater drainage and aeration, which allows the roots to grow much deeper and reach more nutrients. The bed itself will be raised, despite the fact that no soil has been added, due to the aeration. It is worth noting that hard, unworked soil should be double dug each season until the soil has attained good structure and long lasting aeration. During subsequent seasons, it can be single dug with a spading fork until compaction again becomes apparent. After double digging the first season, deep tilling during subsequent seasons can be quickly accomplished with a u-bar, particularly in the cases of larger minifarms or commercial farms.
- In order to plant intensively, beds are 4 to 6 feet (1.2 to 1.8 m) wide, usually 5 ft (1.5 m) and at least 5 feet (1.5 m) long, often 20 feet (6 m), forming a bed of 100 square feet (10 m²). Crops are not planted in traditional rows according to a square pattern, but are planted in a hexagonal or triangular pattern in the bed so that no space is left unnecessarily unused. These wide beds and close spacings not only allow more plants per area, but also enable the plants to form a living mulch over the soil, keeping in moisture and shading out weeds. Additionally, whenever possible seedlings are started in flats so that more garden space is available to large plants and so that the seedlings can be more closely spaced before transplant, forming a living mulch in the flat as well.
- Companion planting is described as taking place both in space, which is traditionally called companion planting, and in time, which is traditionally called crop rotation. Companion planting can be used to improve the health and growth of crops, and also as another form of intensive planting, which uses vertical space more efficiently by mixing shallow rooting plants with deep rooting plants or slow growing plants with fast growing plants.
- In order to achieve sustainable fertility on a closed system basis, the biointensive method uses carbon and calorie farming, an aikido-style of work, composting—including safe and legal human waste recycling, the use of open pollinated seeds, and limited land use, which allows farmers and gardeners to retain more of the land in a wild state for genetic diversity.
- If carbon or compost crops are grown in about sixty percent of the cultivated land, they can provide the compost and thus the fertility for one hundred percent of the cultivated land. Many cereal crops qualify as compost crops, providing both food and abundant compost. Additionally some of these compost crops may be grown during the winter, when the land would be otherwise unused. Certain compost crops are higher in carbon while others are higher in nitrogen, and the desired proportion of each must be grown. Also, certain compost crops take particular desired nutrients from the subsoil and concentrate them in the compost. This proportion of 60 % compost crops is crucial to the sustainability that is the goal of the biointensive method, and to the fertility of one's garden.
- In calorie farming, care is given to growing enough food energy (and other nutrients) to live on in a minimal area. Root crops also allow biointensive farmers and gardeners to grow more nutrients in smaller areas, resulting in less labor and more space for wilderness and other people. These crops—which have both a high calorie content per pound, and a high yield per area—include potatoes, sweet potatoes, garlic, leeks, burdock, and parsnips. About 30 % of the land cultivated for food is used for root crops.
- Composting allows the plants to transform and enrich the soil with organic matter, and also to return nutrients to the soil. Biointensive composting is fairly straightforward, emphasizing the health and diversity of the microbes that break down and become a part of the compost. Thus, relatively cooler composting is practiced, and plant materials are preferred over animal materials. Soil is often combined with the compost to inoculate the pile with microbes. Without human waste recycling, however, nutrients and organic matter are constantly removed from the soil and flushed away. Therefore, when safe and legal human waste recycling is possible--as in many places it already is--that fertility can be returned to the soil. A great unappreciated source of compost and soil improvement is the roots of crops themselves, which are left to decompose in the soil, and help to both fertilize and sew it together. Thus crops such as cereal rye and alfalfa, which have exceptionally deep roots, are valued.
- The use of open pollinated seeds ensures genetic diversity, and allows the farmer to be self sufficient, harvesting seeds from his or her own plants, and cultivating varieties which are best suited to that particular region.
- Retaining half the land in a wild state also allows for genetic diversity.
- An aikido style of working which conserves energy and thus requires less food energy, is more efficient, and thus enables one to get more work done, leaving time for other pursuits.
Because some of these techniques result in intensive productivity, the system must be practiced as a whole in order to prevent soil exhaustion. Although the goal of the biointensive method is sustainability, if the techniques concerning productivity are practiced without the techniques concerning sustainable fertility, the fertility of the soil may be used up even more quickly than with normal unsustainable methods. The most important element for sustainable fertility is the growing of sixty percent compost crops, composting, and when possible safe and legal human waste recycling.
The biointensive method concentrates on the vegan diet as the easiest to raise on the smallest amount of land. This does not, however, mean that biointensive excludes the raising of animals. A diet which incorporates animal products can be raised biointensively, without grazing. Although this uses the land less efficiently than a vegan diet raised biointensively, it is more space efficient than typical methods of raising animals.
- John Jeavons, How to Grow More Vegetables: And Fruits, Nuts, Berries, Grains, and Other Crops Than You Ever Thought Possible on Less Land Than You Can Imagine ISBN 1-58008-233-5
- Carol Cox, John Jeavons, The Sustainable Vegetable Garden: A Backyard Guide to Healthy Soil and Higher Yields ISBN 1-58008-016-2