Though we often think of soil testing as a spring chore, fall is actually a better time. At LawnAmerica, we offer soil testing for a $20 fee, working with a laboratory in Ohio, and can send you results within a few weeks. We can test your lawn, or if you have a garden, are happy to do that also.
With lawns, we are mainly looking at what your soil pH is. The acidity or alkalinity of a substance is measured in pH units, a scale running from 0 to 14, with a pH of 7 being neutral. As numbers decrease from 7, the acidity increases. As numbers increase from 7 so does the alkalinity. Soils generally range from an extremely acidic pH of 4 to a very alkaline pH of 8. This range is a result of many factors, including a soil’s parent material and the amount of yearly rainfall an area receives. Most cultivated plants and turf enjoy slightly acidic conditions with a pH of about 6.5.
If a soil test shows the pH not being in the preferred range from about 5.8-7.2, we’ll recommend several treatments of either lime or sulfur to amend the soil. At very acidic or very alkaline levels, certain soil nutrients are tied up in the soil and not available. So, the nutrients, such as Iron for example, may be in the soil, but the plant cannot utilize it if the pH is too alkaline. With acidic soils, nutrients such as Phosphorus and Potassium are tied up and not available. So with low pH soils, we’ll apply granular lime to raise the pH gradually. On alkaline soils, we apply granular sulfur to help lower the pH. No more than two treatments per season should be applied, and late fall is a great time to do so if needed.
If your soil test suggests more organic matter, and most soils in the urban areas of Oklahoma are short of this, fall is a much better season to add organic matter to gardens or lawns. Materials are more available than in the spring, and fresher materials can be used without harming young tender spring-planted plants. Generally, the more organic matter in the soil, the better for your plants.
Most Oklahoma soils have adequate levels of Potassium and Phosphorus, and Nitrogen is always going to be needed, as it’s utilized by plants or is lost in other ways. If a soil test shows low levels of these primary nutrients, we can adjust our fertilizers used on your lawn and/or apply a supplemental treatment during the late fall, winter, or early spring. So contact us now for a soil test, and if the soil chemistry is not ideal, it’s a good time to begin applying amendments to correct.