Thick, heavy red clay soil is no fun to work with in the garden. It turns soupy and sloppy in wet weather and rock hard in dry weather. Clay soil has poor drainage, may inhibit root growth and is often not very fertile--and few garden plants will thrive in red clay soil. Adding organic matter such as compost or mulch will help improve heavy clay soil. You can also grow vegetables in red clay using an easy, no-till layering technique known as lasagna gardening. It's relatively easy, but will take a few months to prepare the soil.
Cover the area where you would like to have a vegetable garden with six to 10 sheets of newspaper or a single layer of corrugated cardboard. Avoid newspaper or cardboard that is glossy or printed with colored inks. There is no need to remove any existing grass, weeds or other plants. In fact, leaving them in place to decompose will add some vital nutrients and organic matter to the soil. Wet down the newspaper or cardboard thoroughly to keep it from blowing away while you work and to hasten decomposition later.
Spread an inch or two of compost over the newspaper or cardboard. If you do not make compost at home, it may be purchased from any garden center in 50-lb. bags, or you may be able to get large bulk quantities delivered directly to your garden site. Compost improves the fertility of your soil. You may also substitute topsoil for compost.
Cover the compost with an inch or two of organic mulch, such as straw, leaves, dried grass clippings or finely shredded bark. Mulch will allow for air circulation, and as it decomposes will add nutrients to the soil. Continue layering compost and mulch until you have built up your garden site by at least 6 to 8 inches.
Top off your garden with an inch or two of topsoil, available in 50-lb. bags or in large bulk amounts. Make sure the topsoil is of high quality. It should be crumbly and black or dark brown, and should not contain much sand, stones or clay.
Wait one to six months for the newspaper or cardboard to decompose so the roots of your vegetables will be able to dig into the existing soil underneath. You may plant your vegetable garden immediately if you dig down through the newspaper with a small hand trowel for each plant.
Add another layer of compost and mulch to your vegetable garden every year.