A Few Thoughts on Organic Gardening - 4. Bare Ground and Tillage

Soil Care: Bare Ground and Tillage

Avoiding bare ground

The quality of your soil depends on the quality of life for the microbes, earthworms, and other organisms in it. That quality of life is best nurtured and protected by keeping a cover on the soil at all times. Bare soil dries out, hardens, bakes in the sun, freezes—all conditions that are hostile to soil life. Keeping a cover on the soil helps maintain a cool, moist environment in which earthworms and microbes thrive. And it helps maintain that “crumb” structure in the soil that aids absorption and retention of water and oxygen. Remember, too, that bare soil is subject to erosion by rain, especially if on a slope of any angle at all, and by wind when the soil becomes dry.

I’ve already referred above to two major ways to keep the soil covered—mulches and cover crops. There is a further way to keep a close cover over the soil: close planting in wide beds. The gardener would do well to grow exclusively in wide beds, rather than in rows with footpaths between each row.

Plants growing closely in wide beds shade the soil, keeping it cool and moist. A couple of strategies:

Dense plantings which are successively thinned: It is possible to plant crops such as lettuces or cooking greens quite close together—much more closely than their full-grown size would permit. As the young lettuces grow and their outer leaves crowd each other, we harvest every other plant for those welcome, early spring salads. By the time the plants are fully grown, we have eaten many a fine salad, but the bed has been under close shade cover the entire time.
Interplanting: Faster growing crops can be interplanted with slower ones to fill the space and keep the soil shaded. For example, lettuces, arugula, broccoli raab and other cooking greens, etc. can be interplanted with cabbages or broccoli. As the plants begin to crowd, we harvest the faster-maturing salads and greens, and the later crops expand to keep the ground covered. Carrots, which are in place much of the season, can be interplanted with radishes or beets, which are harvested before the carrot tops get bushy enough to shade the entire plot.

Minimizing tillage

So many of our garden efforts are bent toward the goal of improving our soil structure—loosening it, making it more workable, opening it up to air and water, protecting and enabling the zone of most intense life in the top three or four inches. Why would we take any action that would break down that more friable structure we have worked so hard to develop? Yet a common, almost universally used garden practice tends to break down soil structure. That practice is tillage.

The farmer plows his field with heavy steel plows that bite deep into the soil, inverting the layers of the soil—the more biologically active top layer is buried under the deeper, less active ones. The home gardener achieves the same result with a power tiller, pulverizing the crumb structure of the soil and blending soil to eight inches or more into an even mix. It is even possible to achieve the same effect through deep digging/inverting with a spading fork.

Another problem with excess tillage is erosion. I have already referred to erosion of bare soil by wind and rain. However, there can be as well an oxidative erosion of the humus content of the soil by excess tilling. When we turn over the soil, we over-expose it to oxygen, which combines with the humus and breaks it down more rapidly.

My practice is to do as little tillage as I can get away with. To be sure, such an approach is easier done after the soil has undergone considerable improvement when the soil is deep and friable and easily worked. Soil in such condition is already loose enough for most crops. If there is a need to further loosen the soil in the bed, the broadfork is the ideal tool.

The broadfork has two wooden handles about shoulder height and a little more than shoulder width. The handles are attached to a heavy steel bar, on the bottom of which are welded twelve-inch pointed tines of heavy steel. The gardener sets the tines into the center of the bed, steps down with full weight of one foot on the bar to push the tines in full depth, then rocks the tines once back and forth. She then pulls the tines back about three inches and repeats. In this way, she loosens the soil to a depth of twelve inches in successive passes, all the way down the bed, then starts from the middle of the bed on the far end and loosens the other half of the bed. Note, however, that though the soil is loosened to the depth of most crop plant roots, there is no inverting of the soil layers: The most biologically active layer stays at the top, where it should be, and the crumb structure of the soil is not lost. And—oh, joy!—there is no fouling of the tines of the broadfork, no stopping in the middle of the work to remove a tiller’s tines and rip off an accumulated tangle of stems and roots.

The broadfork is one of those tools which make good use of the whole body. Its use is rhythmical and sweet, and draws the mind into a meditative awareness as the work goes on. It is a true joy to use.

Of course, it is a joy only in deep, mellow soil. In compacted, unimproved clay, it is a great deal of hard labor. But then, so is the use of any power tiller made, in tight clay. Let’s face it—we pay our dues when opening up new ground for garden, whatever tools we use to tear up an existing sod and dig up the dense, tight soil. I strongly urge the use of deep, heavy-rooted cover crops, liming, and other means discussed above to loosen the soil at depth as soon as possible, rather than fight with a noisy, vibrating, stinking tiller even one season.

For those who doubt the sincerity of what I’ve said about my preference for the broadfork, know this: I cultivate a total garden space of about 5000 square feet. I have used both a Troybilt rear-tine tiller and, more recently, I owned a Mantis. After using the Mantis less and less each season, about three years ago I passed it on to a neighbor on “permanent loan,” with the understanding he would maintain it, but I could bring it over for a job now and again if I needed it. I have not done so, and can no longer imagine doing so in the future. I’ll admit it—I’m the sort of guy who takes the easy way out.

A Few Thoughts on Organic Gardening – 4. Bare Ground and Tillage

Table of Contents

Soil Care: Bare Ground and Tillage

Avoiding bare ground

Minimizing tillage