Periodic soil testing will help to correct nutrient deficiencies, avoid excess fertilizer applications and maintain a healthy lawn. Annually when attempting to correct a nutrient deficiency or change the soil pH. When fertilizers containing phosphate or potash have been used on a regular basis for a number of years. Your local University Outreach and Extension center has soil sample boxes available for use at no charge. Using a small shovel or soil probe, sample to a 3 inch depth on established lawns or, before seeding, to a 4-6 inch depth. Take 12 or more random cores from each area of the lawn to be tested and remove the thatch and live plant material before breaking up the cores and mixing thoroughly in a dry plastic bucket.
Air dry the sample overnight before sending.
If your lawn has areas with distinctly different soil conditions that need to be considered separately, collect soil samples from each area. After processing your sample, the testing lab will send you a soil test report. A pH of 7.0 is neutral, less than 7.0 is acid, and greater than 7.0 is alkaline. Most of the essential plant nutrients are available at optimum levels between a pH of 6.0 and 7.0. Limestone is used to raise the pH of acid soils, resulting in greater availability of soil nutrients.