Importance of a Soil Sample
How does soil pH affect turf health and growth?
Soil pH is an important chemical property because it affects the availability of nutrients to grass. Nutrients (both macro and micro) supplied to a lawn as part of a maintenance program will be utilized most efficiently and will have the best impact if the pH of the soil is within the proper range. The pH of soil is measured on the pH scale from 0 to 14, with 0 being the most acidic and 14 the most alkaline. The ideal pH range for both fescue and Bermuda grass lawns in our region is 6.2 and higher. It is possible for the soil to be too alkaline, but due to our soil conditions in Virginia, it is extremely unlikely.
How is soil pH determined?
To measure soil pH, a soil test should be performed. Do-it-yourself soil test kits are available but the best method is to send a sample to a professional lab. Virginia Green is partnered with an independent laboratory and they handle all our soil testing. Samples are collected with a soil probe which is a hollow metal, cylindrical tool that pulls a core of soil. Multiple core samples are taken from throughout the turf areas and combined within a bag to be sent to the lab. This process will yield an average pH result when the test is performed.
If the soil proves to be acidic, how is acidity reduced?
If a soil test comes back with a pH below 6.2, an application of limestone is the best way to raise the pH of a soil and therefore reduce acidity. Either granulated or powdered lime can be utilized. However, granulated lime is preferred because the powdered form can drift in the wind when applied resulting in an uneven application. The amount of lime needed to effect change in pH can be determined by a landscaping professional, such as an agronomist. Lime supplied to actively raise pH levels is often referred to as a corrective lime application. Absorption of the lime and change in pH can take as long as 8 to 12 months. After that time, it is a smart agronomic practice to test the soil once again and see if potentially more lime is needed. It is worth noting that lime also supplies the micro-nutrients calcium and magnesium. Determining and correcting soil pH, if necessary, is a process that should always be done to ensure a lush, healthy, green lawn!