This is the time of year that everyone is asking about how and when to fertilize their pastures, lawns, and gardens. My favorite request is “could you come out to my house and look at my lawn or pasture and tell me why I can’t grow anything?” I’ve looked at many pastures, lawns and gardens over the course of my fifteen years as an Extension agent. We can stand in a field and speculate what might be wrong all day long, but we would never really answer the question.
More often than not, the problem is associated with poor fertility or low soil pH. The only way to truly answer the question is to pull a soil sample to have it tested at our lab. Don’t waste your time and money trying to guess how much fertilizer you need. A soil test is the quickest and easiest thing you can do to rule out a potential problem. If the soil test comes back good, then we can move on to ruling out other issues.
The Extension office has a drop box for accepting soil samples at 320 West Cherokee Avenue in Cartersville. We can accept your sample anytime, including nights and weekends. Soil tests cost $9 and take about a week to get the results back from our laboratory at UGA. Please include your contact information with your sample so we can follow up with you for payment over the phone. If you prefer, you can also order a soil test kit from home for $15 by going online to soiltest123.com.
Whether soil testing a lawn, garden, or pasture, be sure to pull the soil from several spots at random (from as many as 10 to 20 spots for larger farms) to get a good representative sample and mix the sample thoroughly in a clean, plastic bucket. Sample each spot at about 4” inches deep for lawns/pastures and at least 6” inches deep for fruits/vegetables. At least a pint of soil is needed per soil sample to be tested. You may submit samples in a pint-size freezer bag if you don’t have a soil sample bag from the Extension office.
One sample, mixed together from several spots, can represent up to fifteen acres if taken properly. Be sure to indicate on the bag where the sample was taken and what is being planted or grown. The Extension office will send your soil sample to our lab at UGA to be tested and provide an exact pH and nutrient analysis with recommendations on how much fertilizer and limestone to apply, if any is needed. For most situations, soils need to be tested every few years to make sure your pH and fertility stays on target.
The next question is when should we apply fertilizer? For summer vegetables and warm-season grasses such as bermudagrass and zoysiagrass, fertilizer should never be applied until soil temperatures average 65F degrees or above. This temperature threshold is important for roots to be actively growing and able to take up the fertilizer efficiently. Soil temperatures in North Georgia can fluctuate widely during the months of March and April.
If you apply the fertilizer too early, it will either leach from the soil or be taken up by weeds before your lawn or garden can use it. Soil temperatures usually do not stabilize until around the end of April or early May—which is the best time to start fertilizing (and planting). Note that winter vegetables and cool-season grasses such as tall fescue can take up nutrients in the fall (October/November) and late winter (February/March) when they are actively growing. One other consideration is how much fertilizer to apply on your pasture, lawn, or garden. Note that most soil test results come back from the lab with a fertilizer recommendation that is intended for the entire season. Although you could apply the fertilizer all in one slug, that’s really not ideal for your plants. In most situations, it’s better to divide the fertilizer into two or three applications about a month apart. This approach allows your vegetables or grass to grow more uniformly and avoid excessive growth spurts that are more vulnerable to insect or disease issues.