Healthy topsoil is essential to growing a productive garden. Topsoil, whether it has been worked for years or never touched, loses vital nutrients due to erosion, compaction and exposure to harmful herbicides, pesticides and other chemicals. Copper, magnesium, sulfur, nitrogen and calcium contribute to the composition of fruits, vegetables, herbs and flowers, each playing its own role in the growth process. Creating healthy topsoil requires several elements, including minerals, air, water, growing plants and decaying plant matter, in and on the soil.
Take soil samples from several points in the planting area to your local agricultural extension agency for testing. Test results indicate pH and mineral levels, giving you a framework from which to restore topsoil to healthy levels. The extension office will help determine which amendments are necessary.
Till topsoil, at a depth of at least 4 inches, before adding amendments. This loosens the soil and incorporates air.
Cover the planting area with 3 to 4 inches of sand and organic compost, such as peat moss, grass clippings, shredded bark, decomposed plant materials, well-rotted manure and worm casings. Add dolomitic lime or rock sulfur at this time, based on recommendations from the agricultural Extension agent, if the pH level needs adjustment.
Work the compost and other amendments into the soil with a garden tiller or pitchfork. University of Illinois Extension recommends working amendments into the soil at a depth of 6 inches.
Rake the topsoil layer to break up any remaining clumps and create a smooth, workable planting surface.