The benefits are slim
Photo/Illustration: Steve Aitken
One of the most common reasons people till the soil is to add air that we have squeezed out of it by tromping back and forth or rolling over it with our wheelbarrows, garden carts, and tractors. It’s true that soil needs air, but we don’t need a tiller to add it. In my vegetable and flower gardens—where I haven’t tilled the soil for more than two decades—I avoid compaction by limiting all traffic to permanently designated areas such stepping-stones among my flowers (photo, right) and paths around my vegetables. Each vegetable bed is only 3 feet wide so that I can reach in to plant, harvest, and weed with my feet firmly in the paths.
Another reason gardeners start up the rototiller is to get organic matter and fertilizers down into the soil where plants need them. But because most of a plant’s feeder roots lie in the surface layers, where biological activity and aeration is best, there is really no benefit to burying these materials deep within the ground. Instead, make those additions the same way nature does: by laying or sprinkling them on the surface.
Tilling is also supposed to kill weeds. This benefit, while real, is a smoke screen because, at the same time that existing weeds are killed, seeds buried within the soil are stirred awake. These weed seeds have lain dormant waiting for light and more air to awaken them, which is just what tilling the soil does—just as if weed seeds were being sown. I, along with many other gardeners, have dramatically reduced weed problems by merely abandoning tillage, an effect that studies by scientists at the U. S. Department of Agriculture have confirmed. Weeds are most easily and effectively done in by using mulches or a sharp hoe. Larger weeds, which should be few if hoeing is done regularly, are best yanked out of the soil, roots and all.