Southern soil is a mix of soil types that include clay soil in the mountainous piedmont regions near the Appalachians, loamy soil in the delta areas and sandy soil along the Atlantic and Gulf coastal regions. The majority of the South also falls within temperate and subtropical USDA hardiness zones 6 through 11. To properly plant seeds you must determine your soil type and USDA hardiness zone and work within these constrictions.
Test your soil by digging 1 quart of soil from up to 10 locations in your garden with a shovel. Place the soil in a bucket and stir. Allow the soil to dry and measure out 1 cup of the soil. Pick plant material, rocks and debris out of the cup of soil. Place the soil in a plastic sandwich bag and take it to your county extension service. An agent with your county extension service will send your soil to the agricultural college soil testing service for a small fee. Most soil testing services send test results back in three weeks. The test results will reveal the soil's structure and pH. Soil testing results will also make recommendations on how to improve soil by adding certain amendments.
Break up your soil with a rototiller to a depth of 12 inches. Spread a 4-inch layer of soil amendments over your soil based on the recommendations made by the soil test. Amendments for heavy clay include gypsum to break up the soil, compost and peat moss to aerate the soil, composted manure to improve the nutrient structure and lime to raise the pH of clay soils, which are often very acidic. Amendments for sandy soils include organic amendments such as compost and peat moss o retain water and add nutrients back to the soil, as well as lime to replace calcium that has leached from the soil. Mix amendments into the soil using the rototiller.
Determine your hardiness zone and the last average frost date for your zone (see Resources). The last average frost date is different for each temperate zone and is made up of the average of yearly last frost dates for the preceding years. You can find this information in the farmer's almanac. Most seeds may be planted up to two weeks prior to the last average frost date. Most seed packets also have a small USDA hardiness zone map printed on the back of them along with a list of the best planting times for each USDA hardiness zone.
Smooth out the soil with a rake and create furrows and drill holes for your seed. Drop each seed into the row or drill hole based on the planting depth listed on the seed packet. If no information is given on the seed packets, plant each seed between two and four times as deep as the seed's width at its widest point. Plant a generous portion of seed. Space the seeds twice as close as your desired plant spacing. Many of your seeds will fail to sprout. As the seedlings grow you will thin them out to the correct seed spacing.
Cover your seeds with soil and water them. Water stimulates germination.