About pH and Limestone

Why is Limestone Important to a Lawn?

High Calcium Limestone is a mined material consisting primarily of Calcium Carbonate. The Carbonate is the part of the molecule that has acid neutralizing capabilities.

Why use Limestone on turf?

  • To neutralize fertilizer and soil acidity thereby releasing nutrients from the soil for plant use.
  • To provide Calcium, an essential nutrient for plant growth.
  • To develop and maintain a desirable soil structure and turf growth.

What benefits can I expect from Limestone?

Major and secondary nutrients are most available at a pH of 6.5 to 7.0. Therefore, fertilizer dollars are not wasted when the soil is in this pH range. The calcium in Limestone is necessary in maintaining a desirable soil structure. Moisture and air movement through the soil is essential for plant growth. Calcium keeps the soil mellow and crumbly, encouraging plants to root deeper and grow faster. Because the soil is more open, it readily absorbs rainfall, thereby cutting down run-off and erosion. This also helps eliminate wet spots that otherwise would remain after the rest of the turf is dry. The combination of near neutral pH and an open, well-aerated soil provides the best environment for microorganisms that decompose organic matter, convert fertilizers to usable nutrients, and fix nitrogen from the air to the soil.

What application rates should be used?

Apply 50 - 100 pounds per 1000 square feet for pH correction, depending on type of limestone used and the severity of the pH level of the soil. Soils with a pH level of 5.9 or lower are considered critical and should be treated to increase the pH level to 6.0 or higher. Generally speaking, 50 pounds of pelletized limestone will increase the pH level of the soil 3 - 4 points on the scale. A Soil Test (preferred) or a pH Meter should determine the pH level of the soil. Maintenance applications should consist of applying 2 - 4 pounds of limestone for each one pound of actual nitrogen applied to the soil each year. Limestone may be applied to the soil at any time. However, the preferred time of application is in the late fall.