Does Lime Hurt Grass?

Definition

• Often simply called lime, agricultural lime is also known as ground limestone and according to West Virginia University, it is a compound of calcium or calcium and magnesium. The three types of lime include calcium carbonate, which is the most widely used in the United States -- about 95 percent of lime used -- and the least expensive. Burnt and hydrated lime are more effective but more caustic than calcium carbonate.

Benefits of Lime

• A major benefit of lime is counteracting the harmful effects of acidic soil by neutralizing it, or sweetening it up. Lime also reduces the toxicity of such elements as aluminum, manganese and iron and aids in regulating zinc, copper and phosphorus while increasing bacterial activity. Additionally, lime adds calcium and magnesium, two important nutrients, to soil.

Testing

• Before purchasing, let alone applying agricultural lime, it is wise to test the pH balance of your soil to find out whether the grass needs lime. Washington State University Extension Service advises a pH between 5.5 and 7.0 for turf grasses, and West Virginia University says most lawn grasses do best between 6.5 and 7.0. Sending samples to a local extension office or testing center will give the best results, but you can purchase a soil test kit or pH probe from many garden centers.

Application

• Again, apply lime only if you have acidic soil. The best time to apply lime to grass is when preparing the soil for planting. If already established, apply lime in the fall or spring, avoiding heat as it can burn the grass. Don't apply with fertilizer or other chemicals. This can damage the grass you are trying to help. Consult the local extension office or gardening center for recommendations in your area.