Master Gardeners In the Garden
Ditch the tiller to try a different approach to gardening
By Bonnie Orr
WSU Chelan/Douglas County Master Gardener
I am going to suggest an alternative to till gardening based on the science of soil. Using a garden tiller may seem like easy work, but in the long run it causes much more work.
The soil is made up of individual particles of sand, clay and silt organized to incorporate air and water. It is not an inert mass, but a substance of living matter. Garden soil contains organic materials — large invertebrates like worms, centipedes, sow bugs, beetles — and thousands of micro-organisms that include mycorrhizal fungi and bacteria.
All these organisms create healthy soil. They break down organic matter so the plant’s roots can absorb the nutrients. The worms create tunnels that guide water below the surface and places for roots to easily move through the soil.
The living matter in the soil works together to make beneficial micro clumps that include pores, or open spaces, between the clumps. Healthy soil is 50% clumps, 25% water and 25% air.
When garden soil is pulverized by a tiller, all the soil structure disappears and there are no more soil clumps, no paths for water, no paths for roots and no place for air exchange, and many of the invertebrates are left dead. Often the soil becomes compacted when it is watered. All the remaining organisms must start rebuilding the soil structure from scratch.
Tilled soil often becomes compacted and hydrophobic, which means the water sits on the surface an inch or so rather than running down into the soil. This, in turn, creates a hard crust on the surface of the soil.
And need I mention that tilling brings weed seeds to the surface so they can germinate?
Along with not tilling, consider another change in the garden regimen: Don’t pull up the plants in the fall when they have been killed by the frost. Instead, cut them to the ground to get rid of any diseased leaves or pests, but leave the roots in the ground to add organic material to the soil and preserve the structure of the soil. Top the garden with a layer of leaf and grass clipping mulch to feed the worms and their friends over the winter. The soil will be ready in the spring for the gardener to open up little holes and place in plant starts or seeds. You can use a broadfork or spading fork to gently loosen the soil and make room for the plants.
If this sounds too great a departure for your gardening practice, go halfway by not tilling the garden paths. This allows some of the healthy soil structure to remain undisturbed.
If you have a vegetable garden that is a half-acre or so, maybe a tiller is appropriate, but for the typical backyard vegetable garden, tilling causes great damage to the soil.
Also, if you are establishing a brand new garden space, tilling is a great way to get the garden established and to incorporate organic material into the soil.