Soil is made up of three components in greater or lesser degrees. These components are clay, loam and sand. Sand is loose, irregular-shaped rock particles that do not compact. Loam is well-drained and filled with organic material. Clay is filled with tiny particles that compact so tightly that water cannot drain well in it. When an allotment of land is described as having clay soil, it means clay is the largest component of soil in the allotment. The best way to improve clay soil is to increase the ratio of loam in the soil.
Break up the soil in the fall with a plow so it will be light and fluffy in the spring after a winter of freezing temperatures.
Time the soil improvement for the point when clay soil dries sufficiently. Wait until clay soil taken from a depth of 6 inches crumbles when squeezed before working it.
Break up the soil to a depth of 12 inches with a plow.
Spread a 4-inch layer of organic materials, including compost, peat moss, composted animal manure, sawdust and wood chips, over the surface of the soil.
Spread a 2-inch layer of coarse sand and perlite over the organic materials.
Add a 1/4 lb. of nitrogen fertilizer, such as ammonium nitrate (21-0-0), per bushel of wood chips to the allotment to feed microbes and help decompose the wood chips faster.
Plow the organic materials and sand into the soil.