What Is the Best PH in Soil for Most Turf Grasses?

Soil pH

• The best soil pH range for grass is between 6.0 to 7.0, according to the University of Missouri. This range is pretty general because all grass types have their own specific preferred pH range. For example, St. Augustine grass can be grown between 5.0 to 7.5, according to Texas A&M University. Some gardeners get lucky and their existing soil is within the correct pH range. However, it is important to check the range annually or before planting to prevent unhealthy grass.

Improper Soil pH Range

• Soil cannot absorb nitrogen, phosphorous and potassium when it is grown outside of its pH range. Lack of nutrients can cause thinning grass, fungal diseases or stress to the plant. Soil that is too alkaline can cause grass blades to turn yellow. This yellowing is caused from lack of iron or a condition caused by chlorosis. Gardeners may see new shorter grass growth turn yellow before older grass blades. When the soil is too alkaline, the grass cannot produce the chlorophyll it needs for green grass blades. Furthermore, soil that is too acidic can burn up the root systems and prevent grass from establishing.

Soil Testing

• To get a full soil analysis, gardeners should collect soil to send to their local cooperative extension. Cooperative extensions will test the soil and mail back the pH results and soil amendment recommendations. Gardeners can conduct their own soil pH test. Soil pH tests are available at local gardening centers. Dig a 6 inch hole to collect your soil sample. Make sure that the soil is dried out or it could alter the soil pH test.

Soil Amendments

• Acidic soil can be amended by liming the lawn. Gardeners can spread ground limestone across their lawn to raise their pH range. Avoid using more than 100 pounds of limestone per 1,000 square feet of lawn area to prevent burning the lawn, as recommended by Purdue University. Gardeners with alkaline soil must increase their fertilizer application rate by 25 percent to make up for the lost nutrients, according to Purdue University. Use a fertilizer that contains nitrogen, phosphorous and potassium.