Humans have tilled the earth since they stopped being hunter-gatherers and became farmers. The tradition has been to turn over the earth before planting to get rid of weeds and to make it easier to use fertilizers to plant crops. Mechanical tillers have made things easier, but tilling is still one of a gardener’s most difficult tasks.
However, soil scientists are now realizing that tilling interferes with the complex relationship of the soil and the micro-organisms that keep the soil healthy and productive. Tilling also compacts the soil, brings long-dormant weed seeds to the surface sale and adds to erosion. In fact, poor agricultural practices like tilling helped develop the Great Dust Bowl of the 1920s and 1930s.
Gardeners who practice the “no-till” method never disturb the bed once it is established. Instead, they add amendments like compost, manure, peat, lime and fertilizer to the top of the bed. Water and the micro-organisms in the soil pull the nutrients down into the subsoil. Instead of weeding, they use mulch to prevent weeds from germinating. The results of “no-till” gardening: good, spongy soil, rich in micro-organisms and beneficial fungi. This allows the roots of young seedlings to penetrate through the soil.
“No-Till” Gardening Benefits
Aeration and drainage
Earthworms, micorrhizal fungi and other soil organisms are keys to good soil structure. Worm tunnels provide drainage. Their excretions help fertilize the soil and bind the soil to provide for aeration. Gardeners who practice the no-till process say that their vegetable plots are freer of diseases and pests.
Good layers of mulch allow water to pass through into the soil, while shading the soil, keeping it at a more constant temperature. This is especially important along the Upper Gulf Coast, where late spring sun beats down mercilessly on garden beds. The mulch also prevents evaporation, and helps create a moist growing environment.
Most garden beds contain weed seeds which stay dormant until they become exposed to sunlight. Dormant weed seeds will remain dormant indefinitely in no-till gardens. Gardeners can easily remove the few weeds carried in by the wind or birds.
Saves time and energy
Some gardeners till with a shovel, turning over the soil one scoop at a
time. Others use gas-powered tillers. No-till gardeners save time and energy.
Keeping the carbon in the soil
Good soil has a great deal of carbon. Humus, compost and other decaying organic matter provides carbon and other carbon-dependent nutrients to plants. Tilling the soil speeds up the breakdown of organic matter. When this happens, it releases the nutrients too quickly, increasing the need for more fertilizers. Good plant growth requires a slow, steady release of nutrients. No-till gardening promotes this process.
Soil without earthworms tends to be poor soil. A good earthworm population in garden soil is a good indication that the soil is healthy. Earthworms create tunnels which help water and air to filter deeply into the soil. Tilling destroys these structures. In addition, earthworm excretions (called worm castings) are extremely rich in desired micro-organisms and nutrients.
The no-till method reduces erosion. It increases the carbon in the soil, which helps prevent fertilizers and topsoil from being washed away.
Types of mulches
Since mulch is such an important component of no-till gardening, it’s important to know what types of mulches work best. First, remember that mulch and compost are not the same thing. Mulch is organic matter that has not yet become compost.
Good sources of mulch:
- Straw: Excellent mulching material, as opposed to hay, which may have weed seeds.
- Pine straw: Don’t curse the pine needles in your yard. Save them for mulch. Many municipalities and homeowners are using pine straw. It degrades slowly and therefore has a longer life than many other mulches.
- Leaves: A great source of carbon and other nutrients. After all, the largest amount of all nutrients in a plant are in its leaves. There are two easily-fixed problems with leaves. They sometimes tend to mat, and they tend to blow away. Spreading leaves in thin layers and sprinkling a little soil on each layer will help prevent both these problems.
- Newspaper: Since paper is made of wood, these are good sources of carbon. However, newspapers tend to blow away. As with leaves, sprinkle soil between each layer.
- Seaweed: Seaweed has a large amount of trace minerals that plants need. Slugs don’t like it, so it acts as a slug repellant as well.
Gardeners who want less strenuous work, good vegetable production, and continuous soil health might want to give no-till gardening a try.