Tilling, the age-old practice of turning over soil in preparation for planting crops, is most often used for vegetable gardens and farms, although it can also be used to prepare perennial beds and lawns. Tilling has many benefits, such as loosening, aerating and warming soil, but it can cause soil erosion. Forget the idea that you have to till annually to have a productive garden. With a little extra care, you might forgo tilling indefinitely.
The main reason for tilling a vegetable garden is to soften it and add amendments in preparation for spring planting. If you're starting a new garden, tilling also removes grass and weeds, which should be mowed down before you till. The first time you till the garden, aim for a depth of at least 8 to 10 inches, especially if you're planting perennial crops that will be in place for years, such as asparagus (Asparagus officinalis), which grows in U.S. Department of Agriculture plant hardiness zones 4 through 8. Adding 1 to 2 inches of compost, manure or peat moss annually can improve drainage, fertility and soil structure. Some people use a tiller to cultivate, or remove weeds, between rows of vegetables, although a mulch of weed-free straw or grass clippings can eliminate most weeds. If you use a tiller, cultivate shallowly around established plants so that you don't damage their roots.
You can till your garden either by hand or with a tilling machine. Small gardens that have been worked before are easily tilled by hand. Simply spread amendments over the soil and turn the soil with a shovel to a depth of 6 to 8 inches. This process mixes the amendments into the soil while removing dirt clods. After you've shoveled the soil, use a metal rake to smooth it and break up any dirt clods on the surface, because seeds need a fine soil surface to germinate well. For larger gardens, your best bet is a mechanized tiller. Most tillers on the market today are rear-tined tillers. These range in size from small machines weighing less than 30 pounds to 6-horsepower monsters weighing several hundred pounds. Unless you have a large garden, a small to medium-sized machine is sufficient. Tillers can be rented if you don't want the expense of buying one.
When to till your garden is largely a matter of personal preference. Many gardeners till in fall after the harvest is over. The weather is usually cool and dry at this time of year, and tilling in the fall allows the soil to settle before spring planting. Fall tilling is especially important if you're adding raw manure, which can contain pathogens, or lime or sulfur, which takes several months to alter the soil pH. Some gardeners till in spring instead, which works best for established gardens with loose, high-quality soil that doesn't need a lot of amendments. No matter when you till, don't work wet soil, which can ruin its texture.
In recent years, researchers have found that excessive tilling of soil destroys microorganisms, as well as soil structure. Many gardeners use a no-till approach instead, which relies on raised beds and mulches to keep the soil soft and friable. Instead of digging amendments into the soil, they are layered on top and slowly work their way down. If you opt to use a mechanized tiller, only till your garden once every two or three years if possible.
- Mother Earth News: Choosing the Right Tiller
- University of California Agriculture and Natural Resources: Vegetable Garden Basics
- Oregon State University Extension: No-Till Garden Beds Save Water and Labor
- Scientific American: No-Till: The Quiet Revolution
- Sydney Postharvest Laboratory: Horticultural Crop Names and Alternate Names
- Fine Gardening: Asparagus Officinalis (Asparagus)
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