Clay soils compact, keeping air and nutrients from reaching plant roots.
The ball and ribbon test provides an easy way to identify clay soil. A ball of wet clay soil can flatten into a ribbon 2 inches or more long without breaking. Clay soil's negative charge allows it to form chemical bonds with positively charged essential elements such as potassium and calcium, making it more fertile than other soil types. Clay's poor drainage can impede plant growth unless you add substances that increase soil aeration.
Organic Matter
Organic materials come from live or formerly live things such as sphagnum peat, wood chips, grass clippings, leaves, straw, compost, manure, sawdust and wood ash. Wood ash's alkalinity makes it a poor choice as a soil amendment in areas where mineral salts are already a problem. Biosolids -- the byproducts of sewage treatment -- are also organic, but may contain pathogens or toxic metals. Organic animal by-products include eggshell, blood meal and bone meal. It takes a 4-inch-deep layer of organic matter tilled into 12 inches of soil to make a difference in soil texture, aeration and permeability.
Inorganic Matter
Grinding shale and heating it to 2,000 degrees Fahrenheit results in expanded shale, a pumicelike, inorganic substance recommended as an amendment for the "gumbo-type" soil in Texas. Mix a 3-inch depth of expanded shale with a 3-inch depth of finished compost into a 6-inch depth of soil for best results. Other inorganic amendments include vermiculite, perlite, tire chunks, pea gravel and sand. While adding inorganic matter usually improves drainage, it does little to increase soil fertility.
Cover Crops
Cover crops prevent weed growth and erosion and fix nitrogen after harvest, before the next planting season. Common cover crops include annual ryegrass, winter rye, winter wheat, oats, white clover, sweet clover, hairy vetch and buckwheat. Legumes such as peas or soybeans fix more nitrogen in the soil than the grasses.
Gypsum and Sand
Clay soils in some western states have excess sodium. Western-state gardeners add powdered gypsum, an ingredient in plaster of Paris and drywall, to remedy this problem, but only if a soil test reveals a pH below 6. Some gardeners add sand to clay soil in 50/50 proportions, but it must be sharp-sided or it forms a cementlike substance instead.
Related posts
Clay soil has finer particles than silt or sand, making it more challenging to aerate.Among sand, silt and clay soil textures, clay has the least natural tendency to aeration, tending to be highly...
Clay soil can be amended so that plants can flourish.Clay soil is heavy, compacts and doesn't drain easily -- its structure is not conducive to successful planting and growing. Although clay soil,...
Clay soil dries to a hard crust.Clay soils are a common feature near mountain ranges where rock breaks down. The soil is composed of tiny, fine soil particles that pack together so tightly that wa...
If you have clay soil, condition it before planting in it.Clay soil has little organic matter and nutrients in it. To grow grass, flowers or vegetables, you'll need to condition the soil. Clay mak...
Clay soil must be softened to allow plants to grow.Clay soil is often compacted and hard to dig into. It is most often a problem for gardeners and landscapers who attempt to get plants to grow in...
