When landscaping your yard, you will encounter a blend of three types of soil: sand, silt and clay. While the ideal soil blend combines all three into a fertile loam, most soils have unequal amounts, making it a challenge for growing plants. Clay soil, with its small, flaky particles and little air space between them, tends to become sticky when wet and does not drain well. In dry conditions, clay becomes as hard as rock. These conditions can hinder the growth and development of plants. Before landscaping clay soil, you must improve the soil’s structure.
Have your soil tested at least one season before undergoing a landscape project. A soil test will indicate what nutrients are deficient in your soil’s makeup, the pH and how best to improve the structure so plants will thrive. Most states with land grant colleges maintain a soil testing lab in conjunction with their college’s community and continuing education program. Contact your local extension agent for information on how to take soil samples and where to submit them.
Aerate clay soil and break it up by plowing. In small plots of land you can use a garden tiller to do this. Larger plots of land or heavier clay may require a yard tractor and a disk plow attachment.
Purchase soil amendments based on the results of the soil test taken in step 1. Amendments to improve clay soil generally include gypsum or sand for aeration and drainage, compost, peat moss, manure or other organic material to improve nutrients in the soil, and lime to raise the pH in acidic soil. If your soil is very alkaline, you may wish to add sulfur to lower the pH.
Spread these soil amendments over your soil to a depth of 3 inches. Spread amendments by hand, shovel and rake on a small plot of land. For larger projects, you can rent a broadcast spreader to spread the amendments. Then mix amendments into the soil by plowing them with a tiller or tractor-pulled disk plow.
Select plants adapted to growing well in clay soil. Native plants for your region are typically adapted for growing in soil that is characteristic of that region. For example, live oaks grow well in heavy clay soil characteristic of the southeast, while cedar elms grow well in clay soil found in Texas.