How to Fix Sorry Soils
N.C. Cooperative Extension Service
Do you have bare spots in your yard? Have you ever noticed the bare spots along the sides of highways and around shopping centers? I call these areas of poor soil ‘sorry soil’, because they are sorry examples of what good soils should look like. According to the dictionary, soil is the “upper layer of earth that may be dug or plowed in which plants grow.” Life on earth depends on that upper layer of soil because it nurtures the growth of plants, filters our water, and provides habitat for a wide range of living organisms. Soil and plants go together, but when the soil gives out, the plants go away, and we end up with what I call ‘sorry soil’. Farmers have known about sorry soil for a long time. Local farmers call poor, eroded spots in their fields ‘gaulded spots.’ ‘Gaulded’ is not in the dictionary – I looked it up – but I know what it means. A gaulded spot is a hard, usually red, clayey spot in a field, usually a high spot, on which almost nothing will grow. These gaulded, sorry soil spots occur all too often in home and commercial landscapes too, and are very common on the sides of roads.
Soil becomes ‘sorry’ when it is abused or neglected. Abuse can take the form of stripping off the top soil and leaving the clay subsoil. Abuse can take the form of compaction, when heavy equipment, cars, or even excessive foot traffic causes soils to pack down and become impervious. Neglect usually takes the form of soil erosion, when top soil is left unprotected by vegetative cover and washes away in heavy rainfall events. Soils can also suffer from nutrient deficiencies when they are over cropped or not replenished with lime and fertilizer when needed. Soils have three basic layers called A, B, and C horizons. The A horizon is the top soil, and it should be loose and easily dug or tilled. Top soil usually has a sandy texture in this part of the world, and when it rains water should flow through good top soil freely. When the top soil is removed or washes away through erosion, the B horizon is what is left. In Franklin County, the B horizon will be red or orange in color and it will be clay. Red clay is much more difficult to work with than a sandy top soil, and it is easily compacted and can be very difficult for water to penetrate. The C horizon is usually a combination of rock and clay and is what is known as soil parent material. Some soils in the southeast may also have an O horizon, which stands for organic matter. Organic matter is composed of plant debris and decomposing plant parts and is found at the top of the top soil. It is difficult to maintain an O horizon in the south because organic matter breaks down rapidly in our heat and humidity. It is possible to find an O horizon in pastures and lawns with permanent grass cover and the forest floor has a substantial O horizon due to the accumulation of leaves and decaying plants. It is rare to find an organic layer in cultivated or plowed soil because the cultivation speeds up the decomposition of organic matter. If you have all 3 or 4 layers of soil on your property the best way to maintain it and even build it up is to maintain vegetative cover on the soil, and the heavier the vegetation the better. Vegetation holds the soil in place, but also adds organic matter and the roots help open up the soil and provide food for soil improving earthworms.
So if you have a patch of sorry soil in your yard how do you fix it? The first step is to loosen the hard soil. You do this by digging up the soil. Aeration will not loosen compacted soil. Lawn aerators make small holes in the soil but they actually compact the soil in the individual holes. Grass seed will germinate more readily in holes created by aerators but aerators will not correct compacted soil. Hard soil needs to be disturbed at least 10 to 12 inches deep. This is best done by manual digging with a shovel or digging fork or by use of a backhoe. Once the soil is loosened, add and incorporate powdered or pelleted dolomitic limestone and organic matter such as mature compost to improve the chemistry and texture of the newly turned soil. Most of the lawn grasses we grow are not native to North Carolina and need a soil pH of 6.0 or higher. Sorry soils will have a pH of 5.0 or much lower and few plants will grow in soils with a low pH. Have a soil test done on your lawn and your bad spots in particular and apply lime as directed by the soil test report. If you don’t have a soil test, apply lime at 75 pounds per 1000 square feet and till it in. Compost or other organic matter such as pine bark fines should be applied at the rate of 1-2 inches deep and tilled in. Once your soil has been deeply tilled, limed, and had compost or other organic matter incorporated, plant grass seed or plant shrubs, trees, or perennials. You will be amazed at how well they will grow in your newly revitalized soil.