Changing Soil pH
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Changing soil pH under turf
Soil testing is important in turf to help determine the soil pH and fertilization needs, especially for potassium and phosphorus. Acceptable soil pH for turf is between 6.0 and 7.5, but often soil tests show pH levels higher or lower than this.
pH higher than 7.5:
Some firms will recommend applying sulfur to reduce the soil pH of turf when it is over 7.5. Unfortunately, you can only apply 5 lbs sulfur/1000 sq. ft. per application to avoid burning turfgrass mowed at 2 inches or more, and a total of 10 lbs sulfur/1000 sq. ft. per year. These rates are much lower for low-mowed turf such as sports fields, fairways, and greens. At this rate, it will take many, many, many years to lower the pH of a typical Midwest soil that is highly buffered with calcium. Instead, you may be better off slightly increasing the annual nitrogen, phosphorus, potassium, and possibly iron applied to the turf. You can, however, till sulfur at much higher rates into a soil prior to turf establishment to help reduce pH.
pH lower than 6.0:
DO NOT APPLY LIME UNLESS IT IS RECOMMENDED because most Indiana soils under turfgrass do not need liming. A buffer pH or lime index should be calculated for you on the soil test report, which determines the amount of lime to apply. No more than 100 lb. of agricultural lime per 1,000 sq. ft. per application should be applied on higher cut turf. Though lime is slow acting, applying lime immediately after an aerification will increase the rate of pH change. Multiple years of lime application will probably be needed and soil should be retested every other year to document progress. Avoid hydrated lime or 'quick lime" because it can burn grass at high rates.