How to Break Down Clay Soil

Soil types are described by how much sand, silt or clay the soil contains. Although most soil contains a combination of these particles, the exact combination determines the soil's ability to retain moisture and provide nutrients to growing plants. When sand, silt and clay are balanced the soil is considered loam and is ideal for plant cultivation. In some areas of the country, soil is predominately clay, the finest of all soil particles, and requires amendments to make the soil suitable for cultivation of crops.

Organic matter (compost/aged manure)

Coarse builder's sand

Garden tiller

Cover the area with a 3 to 4 inch layer of coarse organic matter. Aged manure that has been sitting for several years is a good choice. Compost can also be added. Avoid commercial compost or composted manure sold in bags at garden supply stores, as they are often too fine to provide the texture you will need when amending clay soil. Seek a supply of bulk materials. You will need one cubic yard for every 100 square feet of garden area. Keep in mind that an area 10 feet by 10 feet equals 100 square feet. Plan accordingly.

Add 3 to 4 inches of coarse builder's sand to the layer of compost. Play sand or sand designed for sandboxes is too fine and will combine with the clay making the soil even more difficult to work. Coarse sand works to break up the clay particles and provides needed texture to the soil. It also increases drainage.

Use a garden tiller to work the compost and sand into the existing soil. Although you can do this by hand for a small area, a tiller does a much better job and makes the work easier. Rent one at an equipment rental center if you do not own a tiller. Till the area from top to bottom. Repeat by tilling the area from side to side. Work until all the amendments are incorporated into the soil.

Avoid working with clay soil while it is wet. It will compact the soil making it difficult to break up in the future.