Centipede grass is a popular warm-season turf known for its attractive, apple-green color and low-maintenance requirements across the Southeast. This turf spreads exclusively through above-ground stems called stolons, which creep along the soil surface and root at various points to create new plants. Although this lateral growth habit results in a dense lawn, centipede grass is naturally slow to spread and fill in thin or bare areas. Accelerating this process requires optimizing the soil environment and management practices to encourage the plant’s horizontal expansion.
Creating the Ideal Soil Foundation
The first step in encouraging centipede grass to spread is establishing the soil conditions it requires. Centipede grass has a distinct preference for acidic soil, which is a significant factor in its overall health and ability to produce vigorous stolons. The ideal pH range is narrow, falling between 5.0 and 6.0, which is considerably lower than the range preferred by many other turf varieties.
A professional soil test should be performed to determine the existing pH and nutrient levels before making any amendments. If the pH is above 6.5, the grass may suffer from iron chlorosis, causing the leaves to yellow. To lower the pH, elemental sulfur can be applied gradually based on soil test recommendations, typically not exceeding five pounds per 1,000 square feet in a single application. Centipede grass also prefers well-drained, often sandy soil, and struggles in heavy clay soils that retain too much moisture.
Nutrient Management for Lateral Growth
The nutrient strategy must be tailored to stimulate horizontal growth over vertical blade height. Centipede grass is a low-fertility grass that requires minimal nitrogen (N) input, often earning it the nickname “the lazy man’s grass.” Applying excessive nitrogen encourages rapid, tall, and weak vertical growth, which detracts energy from the stolons needed for lateral spread and can lead to increased thatch buildup and disease susceptibility.
A general guideline is to apply no more than 0.5 to 2 pounds of nitrogen per 1,000 square feet annually. When selecting a fertilizer, look for blends with a low or zero middle number (phosphorus) and a moderate to high last number (potassium), such as a 15-0-15 or 10-0-20 NPK ratio. Potassium (K) is particularly beneficial as it supports root development, overall health, and stress tolerance. The best time for a single annual application of a slow-release fertilizer is in the late spring or early summer, coinciding with the grass’s peak growth period.
Cultural Practices to Promote Stolons
Routine maintenance practices can encourage the grass to spread. Mowing height is a simple yet powerful tool for encouraging lateral growth and density. Centipede grass should be maintained at a low height of cut, ideally between 1 and 2 inches.
Keeping the grass on the lower end of this range, such as 1.5 inches, forces the plant to focus its energy on producing and strengthening stolons. Mowing should be frequent enough that no more than one-third of the blade height is removed in any single session. This practice reduces stress and provides the consistent light exposure necessary for the low-growing stolons to develop. Watering should be deep and infrequent once the turf is established to encourage a deeper root system, though newly spreading runners may benefit from slightly more frequent, shallow watering to root quickly into the soil surface.
Reducing Competition and Impediments
Physical barriers and competing plants represent significant impediments that must be addressed to allow centipede stolons to spread effectively. Aggressive weed control is necessary because weeds steal light, water, and nutrients, physically blocking the movement and rooting of the runners. Applying a pre-emergent herbicide in the early spring, before soil temperatures warm up, can prevent weeds from germinating and competing with the centipede grass during its active growing season.
Another common barrier to spreading is excessive thatch, a layer of dead and living organic matter that accumulates between the green blades and the soil surface. If this layer becomes too thick (more than one-half inch), it lifts the stolons, preventing them from making solid contact with the soil. Light vertical mowing or core aeration can be performed during the active growing season to break up the thatch and improve soil-to-stolon contact, allowing the runners to root down and establish new growth.