Centipede grass is a warm-season turfgrass thriving across the Southern United States, popular among homeowners seeking a low-maintenance lawn. It is often called the “lazy man’s grass” because it requires minimal mowing and fertilizer compared to varieties like Bermuda or Zoysia. However, its low-maintenance nature means it has specialized nutritional needs. Applying standard, high-input lawn fertilizers can be detrimental. Selecting the ideal product and application strategy requires understanding these unique requirements to keep the lawn healthy and vibrant.
Understanding Centipede Grass’s Unique Requirements
Centipede grass has a slow growth habit, requiring significantly less nitrogen than faster-growing turf varieties. Applying too much nitrogen causes rapid growth, leading to excessive thatch buildup and a weakening of the root system. Over-fertilization is the leading cause of centipedegrass decline, making the turf susceptible to disease and insect pressure.
This turf prefers highly acidic soil, thriving in a pH range of 5.0 to 6.0, with 5.5 being the target. A soil test is important to confirm this range. A higher pH level significantly hinders the grass’s ability to absorb micronutrients, especially iron. When the soil pH rises above 6.0, iron becomes chemically bound and unavailable to the plant, even if present in the soil. This poor nutrient efficiency demands a specialized feeding program.
Selecting the Ideal Fertilizer Formulation (N-P-K)
The best fertilizer for centipede grass is one that strictly meets its low-nitrogen, moderate-potassium needs, often found in specialized turf blends. The N-P-K ratio should feature a low first number (Nitrogen) and a high third number (Potassium), such as 15-0-15 or 10-0-20. A high-potassium ratio improves the grass’s drought and cold tolerance, strengthening overall health without promoting excessive top growth.
The type of nitrogen source is important, requiring the use of slow-release nitrogen (SRN) compounds. Look for fertilizers containing ingredients like sulfur-coated urea or polymer-coated urea. These release nutrients gradually over several weeks or months, preventing the rapid growth spurts and potential leaf burn caused by quick-release sources.
Avoid “weed and feed” products or general-purpose lawn fertilizers, as they typically have a high-nitrogen analysis excessive for centipede grass. Phosphorus (the middle number, P) should be kept at or near zero unless a soil test indicates a deficiency. Centipede grass needs very little phosphorus, and a high concentration can interfere with iron uptake, leading to yellowing.
Timing and Application Methods
The timing of fertilizer application is important, focusing on the active summer growing season. Wait until the grass is fully greened up in late spring, typically around mid-May, before applying the first round. Applying fertilizer too early risks stimulating growth that could be damaged by a late frost. Fertilizing in the fall can hinder the grass’s natural winter preparation.
Centipede lawns require only one or two light applications of nitrogen per year, totaling 1 to 2 pounds of actual nitrogen per 1,000 square feet per season. If applying twice, split the total amount, using 0.5 to 1 pound of actual nitrogen per 1,000 square feet for each treatment. The second application should occur in mid-to-late summer (late July or early August), but never after September 1st to ensure the grass prepares for dormancy.
After spreading granular fertilizer, lightly water the lawn to move the product off the grass blades and into the soil. This watering helps prevent fertilizer burn and initiates the breakdown process for slow-release products. Always calculate the application rate precisely based on the N-P-K analysis to avoid over-application.
Addressing Common Nutrient Deficiencies (Iron and pH)
Centipede grass is prone to developing chlorosis, characterized by yellowing or pale-green leaves, often due to iron deficiency. This deficiency is typically caused by a high soil pH or elevated phosphorus levels. When the soil becomes too alkaline (pH above 6.0), the iron is locked up and cannot be absorbed by the grass roots.
To rapidly correct the yellow color, apply a liquid iron supplement, such as chelated iron or ferrous sulfate, which is immediately available to the foliage. This application is a color enhancer, not a fertilizer replacement, and may need repetition every few weeks.
For a long-term solution, manage the soil pH. A professional soil test confirms the pH level and recommends the correct amount of elemental sulfur or another acidifying agent. Applying sulfur gradually lowers the pH into the preferred acidic range of 5.0 to 6.0, correcting the underlying issue.