The quality of your topsoil is directly responsible to how well your landscape and garden plants grow. A good topsoil, according to the Utah State University Extension, is high in organic matter and nutrient content and is low in salts. Topsoil that is used year on year looses these qualities and requires amending. A high-quality topsoil is dark in color, has a pH from 5.5 to 7.5 for a slightly acidic soil, and is well draining.
Take soil samples from your garden or lawn, place the samples into a plastic container, and send the samples to your local university extension. The soil lab tests the pH level of the soil, and its composition, and will send you recommendations on how to amend it.
Add leaves, grass clippings or compost to your topsoil to improve its structure, suggests the Vermont Cooperative Extension. As the matter decomposes, the material adds nutrients and degrades into fine soil. Apply 3 to 4 inches of organic material to the soil and till in using a rototiller. Organic matter should make up 2 percent of topsoil by weight.
Grow cover crops such as rye grass in the fall to protect the soil during the winter from wind and soil erosion, suggests the Virginia Cooperative Extension. By summer, roots from cover crops decompose, improving soil structure.
Remove large debris such as rocks, garbage and other material from the top soil.
Cover the soil with mulch for several years to improve tough soil such as clay or sand once organic matter is added.