The Extension Service offers low-cost soil testing and will give you detailed advice about how to account for any deficiencies in your soil (what fertilizer you should add). If you have a large area to test, contact the Athens-Clarke County Extension office directly. But if you only have a small plot or are confident the soil is the same across the plot, you can order a postage-paid soil sample kit online, follow the directions to collect a sample, mail it away and receive emailed and printed results.