Centipede grass, a warm-season turf common in the southeastern United States, is valued for its low-maintenance requirements and distinctive apple-green color. Often called the “lazy man’s grass,” it requires far less attention than other popular turf varieties. This low-input nature, however, means it is highly sensitive to the fertilization practices used on other lawns. Applying fertilizer incorrectly can quickly weaken the grass, leading to decline, disease, and yellowing. The proper approach involves understanding its unique nutritional profile before selecting and applying any product.
Understanding Centipede Grass Nutritional Needs
Centipede grass has the lowest nitrogen requirement of the commonly used warm-season turfgrasses, a direct result of its slow-growing habit. Most established lawns only require between one and two pounds of actual nitrogen per 1,000 square feet annually. Over-fertilization with nitrogen is detrimental, often leading to Centipede grass decline, which manifests as yellowing patches and increased vulnerability to disease and thatch buildup.
This turf is also highly sensitive to phosphorus (P), the second number in a fertilizer’s N-P-K ratio. Established Centipede grass should not receive phosphorus unless a soil test indicates a deficiency, as high levels can interfere with the grass’s ability to absorb other nutrients. Phosphorus buildup, often caused by repeated use of balanced fertilizers like 8-8-8, can harm the lawn.
The grass thrives in acidic soil with a pH between 5.0 and 6.0, which is more acidic than what most other turfgrasses prefer. When the soil pH rises above this ideal range, the grass can develop chlorosis, a yellowing condition caused by an inability to access iron, even if the element is present in the soil. Since Centipede grass is not a dark green color, a yellow appearance often signals iron deficiency or another nutrient issue. To quickly address this yellowing, iron supplementation is often necessary, which restores the green color without promoting excessive growth.
Choosing the Appropriate Fertilizer Blend
Homeowners must select fertilizers tailored for low-input turf due to the specialized needs of Centipede grass. The ideal blend for an established lawn features a high nitrogen-to-phosphorus ratio, often with near-zero phosphorus content. Look for NPK ratios such as 15-0-15, 16-0-8, or similar phosphorus-free formulations designed for Centipede grass.
The nitrogen source should be primarily slow-release, which ensures a steady, measured nutrient delivery over an extended period. Slow-release nitrogen, such as polymer-coated urea or sulfur-coated urea, minimizes the risk of burning the grass blades and prevents the sudden surge of growth that can lead to Centipede grass decline. While quick-release nitrogen sources can be used, they must be applied in smaller, split doses to prevent nutrient overload.
Potassium (K), the third number in the ratio, is beneficial for plant health, stress tolerance, and winter hardiness. A fertilizer with a potassium content equal to or slightly higher than the nitrogen content is often recommended for Centipede grass. If a yellowing issue persists despite using a low-phosphorus blend, a liquid iron supplement can be sprayed directly onto the foliage to rapidly improve color within 24 hours.
Optimal Timing for Seasonal Application
Timing the fertilizer application is as important as product selection, as Centipede grass must be fully active to absorb nutrients effectively. The first application should occur in late spring (around mid-May), after the grass has completely emerged from winter dormancy and fully greened up. Applying fertilizer too early, when the grass is still partially dormant, can promote tender new growth that is highly susceptible to damage from a late-season frost.
The most reliable indicator for the first feeding is the grass’s actual growth stage, not a calendar date, ensuring active nutrient absorption. This initial application should deliver between half a pound and one pound of actual nitrogen per 1,000 square feet, depending on the soil type. Lawns growing in sandy soils may tolerate the higher rate, while those in clay soils should receive the lower amount.
If a second feeding is necessary, it should be applied in mid-summer, ideally before mid-August. This second application should be lighter than the first and contains nitrogen and potassium to support summer growth and prepare the grass for fall. Fertilization must cease well before the grass prepares for dormancy, as late-season nitrogen applications can encourage growth that depletes the plant’s carbohydrate reserves and increases susceptibility to winter injury.
The Step-by-Step Application Process
Before applying granular fertilizer, the lawn should be mowed to its regular height (one to two inches), and the clippings should be left on the turf. A soil test should be used to determine exact nutrient requirements, especially for phosphorus and pH. If a test is unavailable, choose a zero-phosphorus, slow-release blend. Using the information on the fertilizer bag, calculate the precise amount of product needed to deliver the target rate of actual nitrogen per 1,000 square feet.
Application is best performed with a broadcast or rotary spreader, which ensures more even distribution than a drop spreader. Spreader settings must be carefully calibrated according to the manufacturer’s instructions to prevent over-application and potential turf burn. To achieve uniform coverage, divide the calculated amount of fertilizer in half, and apply the two halves by walking the lawn in two perpendicular directions.
After the granular fertilizer is spread, light watering is necessary to move the granules off the grass blades and down to the soil level. The irrigation should be brief, designed only to dissolve the outer layer of the granules and prevent foliar burn. Deep soaking is not required immediately after application, as it can cause nutrients to leach out of the root zone, especially with quick-release products.