Amending soil will help plants thrive

A common complaint among gardeners in Southeast Missouri is that the soil they have in their landscape is nothing but clay. When the clay is too wet, it just forms clumps. When it is too dry, it is as hard as a brick. These gardeners can't get anything to thrive in clay soils. Most plants just hang on for dear life.

Before you go to the expense of excavating all of the soil around your home and replacing it with topsoil (which may or may not be really good topsoil), consider using that clay soil as base upon which to build a wonderfully tillable, arable and crumbly soil that your plants can not only grow in, but thrive in.

Clay soils have some good attributes. Clay is made up of small particles bound together by electrical charges. Because clay is made of many small particles, it has more surface area per cubic foot of soil than either loam or sand. All of this surface area is a home for minerals to reside in. Quite often clays have more nutritive value per cubic foot of soil than either loam or sand.

Clay soils also hold moisture much longer than loam or sandy soils. Therefore during a drought there is more moisture-holding capacity in clay soil.

You can use clay soils to your advantage if you amend them with gypsum. With this amendment you can convert your sticky, hard-as-a-brick clay soil into a nice, crumbly soil in which plants will thrive.

When added to your soil, electronic charges in gypsum neutralize some of the charges on the surface of clay particles. I need to emphasize the word some. Not all of the clay particles have their charges neutralized. The result is that aggregates are formed within the soil.

These aggregates will have different sizes and shapes. Within each aggregate you will find many clay particles that are bound together by electronic charges, but each aggregate will be separated from other aggregates. The result is a soil that is now much more crumbly or tillable.

Because these aggregates are of different sizes and shapes, your soil will have more air space in a cubic foot of soil as compared to a non-amended clay soil. These air spaces allow for more moisture within the soil. These air spaces also allow roots to grow more vigorously in the soil. finally, these amended soils will also allow moisture to filter through the soil faster.

If you have an existing lawn or flower bed and want to amend that soil, apply gypsum at the rate of 40 pounds per 1,000 square feet. I would recommend that you make these applications four or five times. I would probably make the applications once per spring and one time in the fall. Therefore it may take you two or three years to get enough gypsum in your soil to do any good.

On an existing lawn or flower bed, gypsum will slowly filter down into the clay soils and do its magic. Don't expect a change overnight. It will take some time for the gypsum to activate.

If you are making a new flower bed, apply gypsum at the rate of 40 pounds per 500 square feet. Till the gypsum into the soil before planting.

If you are making a new flower bed or tilling up your lawn to start over, you can also amend your soil with organic matter. A common, easily-purchased product is peat moss. Apply it at the rate of 3.8 cubic feet per 20 square feet. You will find that the addition of organic matter will speed up the amendment process.

If your landscape base is nothing but clay, consider amending the existing soil. Your plants will love you for it.

Send your gardening and landscape questions to Paul Schnare at P.O. Box 699; Cape Girardeau, Mo. 63702-0699 or by e-mail to news@semissourian.com.