Bermuda grass (Cynodon dactylon) is a warm-season turf known for its aggressive growth and resilience in high-heat environments. When healthy, it rapidly spreads via stolons and rhizomes, creating a dense, durable lawn. A lack of growth indicates that fundamental environmental or cultural requirements are not being met. Diagnosis requires systematically checking conditions from the soil beneath to the maintenance practices applied above.
Soil Quality and Nutrient Balance
The foundation of healthy growth for Bermuda grass is the soil’s chemical balance and physical structure. This turf prefers a slightly acidic to neutral environment, with the ideal pH range falling between 5.8 and 7.0. pH levels outside this range hinder the plant’s ability to absorb essential nutrients. A soil test determines the current pH, guiding amendments like adding lime or sulfur.
Soil compaction severely restricts the movement of air, water, and nutrients to the root system. Heavy traffic or lawn equipment use squeezes soil particles together, preventing deep root penetration. This results in a shallow, stressed root system that cannot support robust top growth. Core aeration creates channels for oxygen exchange, allowing roots to spread into the newly loosened space.
Bermuda grass is a high-demand turf, particularly for nitrogen, which is responsible for the vibrant green color and aggressive spreading. A nitrogen deficiency is visible when older grass blades turn a uniform pale green or yellowish color. This turf requires between two and four pounds of actual nitrogen per 1,000 square feet annually during its active growing season. Without this consistent feeding, growth will be significantly stunted.
Light and Water Stress
Insufficient sunlight is a primary reason for poor Bermuda grass growth. As a sun-loving species, it requires a minimum of six to eight hours of direct sunlight daily to thrive. When grown in shady conditions, such as under large trees, the grass becomes thin and weak as it struggles to produce the energy needed for lateral growth. If a location does not meet this high light requirement, the grass will eventually thin out and fail.
Improper watering techniques, including both underwatering and overwatering, induce stress that halts growth. Bermuda grass should receive approximately one to 1.5 inches of water per week during the growing season. Water deeply but infrequently to encourage the development of deep, drought-resistant roots. Shallow, daily watering encourages weak roots and keeps the surface moist, making the turf susceptible to fungal diseases.
Overwatering leads to a saturated soil environment that suffocates the roots by displacing oxygen. This condition also creates an ideal breeding ground for turf diseases, compromising the plant’s health. Allowing the soil surface to dry out between deep watering events forces the turf to develop a strong root system.
Mowing and Maintenance Errors
Mowing height directly impacts the density and lateral spread of Bermuda grass. Common varieties should be maintained at a low height, typically between 0.5 and 1.5 inches, to encourage dense, lateral growth. Mowing the grass too high causes it to grow vertically, creating a thin, open canopy that allows weeds to establish easily. Consistent, short mowing signals the plant to spread horizontally.
Removing too much of the leaf blade at one time is known as scalping. The “one-third rule” dictates that no more than one-third of the total blade height should be removed in a single session. Violating this rule stresses the plant by stripping away photosynthetic material, forcing it to expend energy on recovery instead of growth. This stress can cause the turf to temporarily yellow or slow its spreading.
Bermuda grass produces a large amount of thatch, a tight layer of organic material. Excessive thatch accumulation prevents water, air, and fertilizer from reaching the soil, impeding growth. Vertical cutting (verticutting) is preferred over traditional dethatching, as it slices through the dense stolons, thinning the canopy and managing the thatch layer.
Invasive Pests and Disease Damage
Pests that feed on roots or leaf tissue cause significant damage. Subterranean pests like grubs feed on the root system, detaching the turf. An infestation is confirmed if the affected grass can be easily lifted or rolled back because the roots have been severed. Mole crickets tunnel near the surface and feed on roots.
Above-ground pests, such as armyworms, feed voraciously on the grass blades, typically at night. A large population can rapidly defoliate sections of the lawn, leaving behind ragged, chewed-down grass. Identifying the specific pest is necessary because treatment requires a targeted insecticide application to stop the feeding and allow the turf to recover.
Fungal Diseases
Fungal diseases inhibit growth by infecting the grass blades, which are the plant’s energy-producing surfaces.
Dollar Spot
Dollar spot is a common disease in Bermuda grass, appearing as small, circular patches that can merge into larger irregular areas. This disease is often encouraged by low nitrogen levels and prolonged leaf wetness.
Brown Patch
Brown patch appears as larger, circular or irregular patches that may have a dark, visible “smoke ring” border. This disease thrives in warm, humid conditions and is exacerbated by overwatering and excessive nitrogen application, requiring cultural adjustments and possibly a fungicide for control.