If you notice discolored yellow patches on your centipedegrass, this may be a sign that the soil pH level isn't appropriate for the turfgrass. Centipedegrass (Eremochloa ophiuroides) is a warm-season turfgrass growing in U.S. Department of Agriculture plant hardiness zones 7 through 10. Improper soil pH levels can leave centipedegrass looking less than desirable, but maintaining the ideal pH for this turfgrass can help improve the look and health of your lawn.
Centipedegrass and Soil pH Levels
Centipedegrass grows best in acidic soils with a pH level that falls between 5 and 6, according to the Texas A&M; Agrilife Extension website. If the soil is too alkaline with a pH level above 6.5, iron chlorosis can occur. The soil should be tested before planting the grass and at yearly intervals. If possible, soil pH levels should be corrected before planting this turfgrass.
Yellowing or pale-green grass blades may be a sign that the centipedegrass is experiencing iron chlorosis. This is typically due to high pH levels in the soil. Even if the soil has proper levels of iron, the alkalinity of the soil prevents the centipedegras from using the iron, resulting in an iron deficiency. This causes the grass blades to change color. Established centipedegrass experiencing iron chlorosis will need frequent applications of chelated iron or ferrous sulfate to maintain its color, according to the University of Hawaii website. However, adding iron to the soil only treats the problem and doesn’t correct it.
Correcting Soil pH Levels
If possible, try lowering the soil pH level by adding sulfur to the soil. Adding 0.75 pound of elemental sulfur per 100 square feet will lower the pH level by one point, according to the North Carolina Department of Agriculture & Consumer Services website. For example, if the pH level is 6.5, adding the recommended rate should lower the level to 5.5. If you cannot correct the pH to the optimum level, the University of Hawaii website suggests changing the turfgrass to a species more suitable for your soil type.
Warnings and Considerations
Sulfur has a low toxicity rate and poses little risk to humans or mammals. However, you should err on the side of caution and keep children and pets, as well as pregnant and nursing mothers, out of the area when applying elemental sulfur. Sulfur dust can cause irritation to the lungs and eyes, and it may cause slight skin irritation. If irritation to skin or eyes occurs, flush the area with ample amounts of water for several seconds.