How to Tell if Your Lawn Needs Lime?
Many lawns in the Northeast, Mid-Atlantic, Southeast, and Northwest are growing in soil that is acidic. The reason I say that all lawns in these areas are not necessarily growing on acidic soil is because soil chemistry can vary from neighborhood to neighborhood. Although not as common, you can find acidic soil in other parts of the U.S.
For example, when I first tested my Georgia clay soil I found that it was acidic and needed lime. After several years of putting down lime, a soil test showed my soil no longer needed lime. I plan on testing my soil every 2 or 3 years.
So what is a soil test all about? The most important measurement is the soil pH. Other info on the test provides values for available phosphorus, potassium, micronutrients and organic matter. As a former County Extension Agent, who looked at hundreds of soil test results for home lawns in Virginia, I know that the primary actionable number to look for is soil pH. You can ignore the other measurements unless one of them shows up as being abnormally low. Soil pH is a measure of how acidic or alkaline your soil is. A pH of 7 is neutral, acidic soil registers below 7, and alkaline soil above 7. Your lawn can tolerate a fairly wide pH range of 5.5 to 7.5, with 6.5 being the ideal pH for growing grass. When your pH is in the ideal range other nutrients in your soil and in the lawn food you spread are more available to your grass plants. When the pH is outside of this ideal range, some of the nutrients get locked up by the soil and your grass can suffer.
Most states offer soil testing through their Extension Service. Check for soil testing labs in your state by doing an internet search with your state’s name and the words “soil testing labs”.
Fall is a great time to spread lime since the upcoming alternating freezing and thawing of your soil can help to transport lime from the soil surface down to lower parts of the soil. If your soil pH is below 5.5, it is not uncommon to need 50 pounds of lime per 1,000 sq. ft. per year over several years. That’s 250 lbs. of lime on a 5,000 sq. ft. lawn. To spread this much lime, you may find you will need to go over your lawn several times with the spreader set at one of the higher settings. You will also find that granulated lime is easier to spread than pulverized or powdered lime.