Topsoil is, as its name implies, the top layer of soil found on the earth. Since it's so close to the surface, it is at ground zero for dying plants, insects and larger animals; as a result, about 10 percent of topsoil typically comes from organic materials. Good topsoil, which is granular and thus provides good drainage, is critical for plants to grow and thrive, especially if the soil below the topsoil is hard, with lots of clay.
Start composting in the fall. Into a compost bin--any large container, at least three feet square. Place a 6-inch layer of organic materials, a mixture of spoiled fruits and vegetables, newspapers, coffee grounds, pet hair, and steer manure. Add a 6-inch layer of dead leaves and twigs, then a 6-inch layer of grass clippings. (After adding the limestone in step 2, start over again with a second layer of each.)
Mix soil from the ground with agricultural limestone (6 parts soil for every 1 part of limestone) and place on top of your compost heap.
Water thoroughly and turn every five to six weeks. Your compost should be ready by spring planting time.
Break up your growing area with a pickax, to a depth of between 18 inches and 2 feet. Break up any masses of hard, chunky soil, an indicator of clay. Remove all rocks and unbreakable chunks of clay.
Dump the decomposed organic materials from your compost bin into your growing area, and mix well with the existing soil. How much you dump depends on the size of your growing area; you should be able to level out all the dirt and compost to a height of no more than an inch over what you had previously.
Dump in a bag of peat moss (follow directions on the bag for the quantity, which depends on how large your growing area is).
Mix thoroughly with your shovel, and then rake to a level finish. Your ground is now ready for planting, with a thick layer of healthy topsoil.