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A Major Question for Gardeners and Farmers PDF Print E-mail
Tuesday, November 18, 2008
Soils are built up and made better by grass, clover and other cover crops They add valuable organic matter, mobilize nutrients and their roots help create good soil structure. A major question for gardeners and farmers is “How do we change what’s growing on our soil, and get it prepared for the next crop?” The complicated answer is tillage, and humanity’s struggling with this is the history of agriculture. The way we till our ground determines to a great extent how well our gardens grow. To grow crops without irrigation, insect problems or diseases requires soft, silky soil that stays loose and friable. Compost gives us the microorganisms which will propagate and help us, but only if we pay careful attention to proper tillage.
The number one rule is don’t work the ground when it’s wet. Take a handful of soil and squeeze it and drop it. If it shatters you are good to go, if it stays in a ball, get out of the garden and wait. Plowing soil that sticks together creates clods that will be with you for years.
The second rule is to go slow and be gentle. Soils are alive and need to be cared for like a baby. Love you soil and it will treat you well.
We use five different tillage implements to turn our cover crops back into production. The first is the moldboard plow, which flips the soil over. I mainly use it in the fall, to turn so. The soil is then left rough plowed over winter, and the freezing and thawing further the metamoprhisis of the sod into soil. We don’t plow deeply though, because we don’t want to bring up the subsoil. Ever so slowly we turn the sod over like we were picking up a sleeping baby. A shovel is the gardener’s plow, used to dig up what’s growing there. If it’s too wet the soil will smear, so wait till it dries up.
A chisel plow, or rebreaker is used whenever we don’t want to flip the soil over. It has several shanks with shoes on the ends, which chip the soil when the springs get tight and then release. This stirs the soil up real well. By waiting a few days between passes through the field the microorganisms have time to help with the breakdown of sod and the formation of humus. Then we run the chisel plow through the soil crossways. The gardener uses a digging fork to accomplish the same goal.
The next implement is the harrow. We use a spike-tooth harrow, to level the ground and make a seedbed, like a gardener would use a rake.  I like to wait a few days, let some weed seeds sprout, and then harrow it again before planting, and this saves a lot of weeding later on.
Plowing only goes so deep. Eventually a hardpan develops below where the plow reaches. A subsoiler sinks into the ground two feet deep and breaks up the hardpan. It is used when the soil is dry, and it leaves cracks in our tight, clay subsoil. This allows access for air and roots, and the soil-forming microorganisms. We enlarge our garden vertically by subsoiling and making our topsoil deeper. A gardener would use a pick to loosen up the subsoil.
Our final tillage implement is the spader, a tool from Italy that makes a bed for planting. The shoe goes in about 5” before it flips the soil over. It is excellent for retaining good soil structure and incorporating cover crops and compost into the garden. A gardener would mimic this double digging, which is removing a spadeful of soil, and then breaking up the lower level and putting the topsoil back on top.
I don’t use a roto-tiller, which beats the soil up too much, creating the illusion of good soil structure. But your nice fluffy soil turns hard after a rain, because the soil particles are all the same size. We’d rather have bigger chucks below, getting gradually finer toward the top, so that after a rain the soil still remains soft and friable.
In a sandy soil a disc works well, but it tends to pack clay soils and create clods. Proper tillage, done slowly, gently and with love for the live soil beings, retains the precious soil structure created by your cover crops. Keep the soil loose so your microbes and crop roots can move around easily and have a good time underground, and your garden will grow great.