Do Not Disturb the Soil
Author: Adair Heuchan, Master Gardeners of Ottawa-Carleton; published with permission
Most gardeners think that turning over the soil in their garden is a good thing and may be surprised to learn that there is a better way. For centuries, farming practices involved turning over or “tilling” the soil, which was thought of as simply the growing medium for plants. Over time, soils were depleted of their nutrients, and agricultural production was unable to feed the growing populations.
The Green Revolution in the 1950s and 60s, championed by Norman Borlaug (Nobel Prize 1970), brought new drought-resistant strains of cereals. Unfortunately, the soils were damaged by the addition of vast amounts of fertilizers, pesticides, and herbicides. These chemicals destroyed the essential flora and fauna, requiring even more fertilizer in order to produce somewhat fertile soils.
Critics of the Green Revolution now point to the loss of biodiversity, including the destruction of wildlife, pollinators, and life generally within the soil. Water quality and health issues have arisen, along with an increase in plant pathogens. Even the deaths of some small farms have been attributed to this Green Revolution.
Soils are Alive
During those heady years of vastly increased agricultural production, few recognized that soils were alive. Soil scientists such as Dr. Elaine Ingham were, however, already studying the worlds of life within the soils. She promoted building aerobic soils full of good bacteria, fungi, flora, and fauna. Her approach was to identify which groups of microorganisms were lacking and to add them through biocompost or bioliquids.
This approach included changing agricultural practices so as not to disturb these essential actors further. Dr. Ingham and others have demonstrated that healthy soils encourage good insects (pollinators), earthworms, nematodes, micro-arthropods, birds, butterflies, and animals to return. They also reject the unwelcome pests. She established the Soil Food Web in 1986 – soilfoodweb.com – to help farmers restore their soils.
Interconnected Systems of Nature
Another key figure was Bill Mollison (1928–2016), an Australian researcher, author, scientist, teacher, and biologist—the “father of permaculture”—who observed the interconnected systems of nature as far back as 1959. In 1974, Mollison and David Holmgren began working together on “permanent agriculture” and published their book Permaculture One: A Perennial Agriculture for Human Settlements in 1978. It promotes an integrated system of ecological and environmental management of humans, animals, plants, and soils. Underpinning permaculture are principles of biodiversity, replicating natural habitats, and non-interference, including notillage of the soils.
Emergence of No-Till Gardening
Many now follow these soil management practices. Two well-known proponents of “no-till” gardening and farming are Morag Gamble and Charles Dowding. Both have dozens of YouTube presentations on building and sustaining no-dig or no-till gardens. In his market garden in Somerset, England, Dowding clearly demonstrates that vegetables planted in nondisturbed soils, covered in 2 inches of compost, thrive better than those where the same compost is “tilled” or even just “forked.”. Even gently opening the soil with a fork disturbs the symbiotic relationship between plants and soil life.
Soils that are essentially balanced and left undisturbed benefit in all kinds of ways. They are more stable and better aerated. They retain more water and percolate it more successfully. They nurture plant fertility and encourage carbon sequestration. Finally, unwanted pests and weeds are not attracted to healthy soils covered in growing plants.
While not a scientific approach, I can say that peas I planted in non-tilled soil were twice as tall and productive as those planted at exactly the same time in a very large pot of fresh potting soil. I am going to try “no-till” in my vegetable patch next spring. There is nothing to lose and potentially much to gain in trying “no-tillage” in your own gardens. Simply add the compost on top in the fall and gently open up the locations for your seeds or seedlings at planting time. Or do it in the spring and top or side dress with compost. In either case, disturb the soil as little as possible and observe the results.