No-till gardening is an idea whose time has come. It's not as simple as just stopping tilling without changing anything else about the way we grow our gardens, but no-till gardening works beautifully as part of an integrated program of ecologically-sound vegetable gardening.
Destroys soil life.
When we till deeply, we completely destroy the soil ecosystem that nature designed to sustain plant life. Tilling shreds fungal networks, kills earthworms and destroys their tunnels, and destroys beneficial bacterial biofilms, all of which work together to recycle nutrients.
Nature’s system was sustainable indefinitely - a closed recycling system for the stuff that bodies are built from - until we started hauling produce and livestock away from the land that produced it, and not returning wastes and bodies to the soil.
Now I’m not saying we should start using our poops in the garden or bury Granddad out back! We obviously can’t do that, but this means we need to figure out how we’re going to replace the minerals we’ve been taking away, because our food is becoming less and less nutritious.
Gardening with nature means helping the organisms that do nature’s recycling down in the soil, so they can do their important job of feeding the plants that feed us. This means no more tilling or use of harsh chemical fertilizers that kill soil life and only replace a few of the minerals that are taken away.
Creates a “hardpan”.
A few inches below the depth that the tiller can reach, a layer of densely compacted soil forms in response to tilling. The weight of the person plus the tiller compacts the soil just below the tiller tines (or plow blade, shovel, etc.) Plant roots have a difficult time penetrating this hardpan layer, which slows growth and nutrient uptake dramatically. Plant roots will hit the hardpan layer and then grow sideways and stay shallow, making the plants more susceptible to drought and requiring more distance between plants.
Destroys soil structure.
Good soil has a structure, created by microbes and plant root exudates, that holds together in a way that helps provide plants with appropriate levels of water, air and nutrient availability. It sounds counterintuitive, but when soil is pulverized by tilling, capillary action doesn’t work effectively to distribute water, tiny air channels that are created by biofilms are destroyed, and nutrients are released that then wash down into the subsoil where they become unreachable or add to the density of the hardpan.
Mixes soil layers. In nature, each layer of soil serves a distinct function, and each has its own unique bacteria and other soil life. Tilling mixes layers and destroys the ecologically-balanced system that nature designed to optimally support plant life.
Releases Carbon Into the Atmosphere
It’s been discovered that humus in the soil used to be a huge bank of sequestered carbon. Large-scale modern agriculture (as well as tilling our own gardens) creates conditions that allow this carbon to oxidize away into the atmosphere. Science is now pointing to modern agricultural practices as a major contributor (perhaps the major contributor) to elevated carbon dioxide levels in the atmosphere.
Tilling does two things that encourage weeds: brings fresh weed seeds up to the surface (which were buried deep by prior tilling), and creates conditions where they can thrive. Since nature is quite ingenious, she tries to “heal” soil that has been damaged by using plants that thrive in harsh soil conditions. We call them “weeds”, which are usually very deep-rooted plants that are able to pull water and nutrients up from deep subsoil. Given enough time, weeds will actually refresh soils that have been damaged by tilling.
Makes plants more chemically dependent.
When soil life is destroyed by tilling, a plant’s “digestive” and “immune” systems are destroyed along with it. Plants can then no longer get the minerals they need, and because of this, they become weak and vulnerable to pests and diseases. We then compensate by feeding them artificial fertilizers and dousing them with pesticides to keep them from being consumed.
No-Till Gardening As Part of An Integrated Program
Beyond the question of “to till or not to till” lies a deeper question. In order to restore our soils to vibrant health we must rethink the entire way we have been growing food. For no-till gardening to work it needs to be part of an integrated program that must also include:
Remineralizing the Soil
This is the biggest step, and to do it properly is not the topic of this article. See the Soil Sample and Organic Fertilizer pages to learn how to figure out what your soil needs and how to supply it. But before we abruptly stop digging, we must get the initial “dose” of appropriate minerals mixed into the top 6” of soil.
Do not believe the many misinformed voices on the web who tell you that enough mulch or compost on the soil surface will supply all the minerals your garden needs “the way nature does it in a forest”. This is false for three reasons: 1) nutrient-dense vegetables are much more “hungry” for minerals than forest or grassland plants, 2) a natural forest or prairie does not get harvested and removed year after year, and 3) mulch, compost and manure no longer contain enough minerals.
Restoring the Soil Life
Most of our soils are suffering from a severe insufficiency of soil microbes, killed off by tilling and artificial fertilizers. Soil microbes serve as an external digestive system for plants -- the mechanism that provides the mineral nutrition they need to survive and be healthy. Just like we need to have healthy gut bacteria in order to digest our food (and have strong immunity), so plants need to have healthy “gut” bacteria in the soil. We can feed our soils a type of “probiotic” to restore these missing microbes. This is also beyond the scope of this article, but you can learn how to do it on the Actively Aerated Compost Tea page.
Most soil life lives in the top six or eight inches of soil. Beneficial bacteria, fungi, actinomycetes, earthworms and other organisms each have a part to play in soil nutrient cycling. Their job includes gathering minerals from a large area, converting them into forms that plants can use, and transporting them into the plant. In return, the plant trades them sugars that it makes via photosynthesis. In a healthy soil/plant ecosystem there are thousands of specific symbiotic relationships that trade specific substances.
In a no-till system, wide growing beds replace narrow single rows, which are never walked on or compacted in any way. After an initial digging-in of minerals* and inoculation with actively-aerated compost tea*, the growing beds are usually mulched with a layer of straw, rotted or shredded leaves, or high-quality compost. (I say “usually”, because if you live in a wet area where slugs are a problem, you may have to forego the mulch.)
Decide how wide to make your growing beds and your paths. I like my growing beds to be about 42” wide, because at 5’2” tall, if they’re any wider than that I can’t reach into the middle. Make your beds twice your reach, so that you can access the middle from the path on either side.To remain loose, friable and porous, you must never compact the soil in any way, so never walk on it or step on it.
(This article is still under construction, check back soon for remaining details.)