St. Augustine grass (Stenotaphrum secundatum) is a favored warm-season turf across the Southern United States and other subtropical regions. This grass is prized for its aggressive growth habit, resulting in a dense, dark green lawn. It spreads laterally by thick, above-ground runners called stolons, creating a mat that crowds out many common weeds. Characterized by broad, flat leaf blades, it has notable tolerance for shade and salt, making it popular for coastal and treed properties.
Critical Care During Sod Establishment
The first few weeks after installation are the most sensitive period for St. Augustine sod, requiring a specific watering regimen. Immediately upon laying the sod, it must be thoroughly soaked so the underlying soil is moist to a depth of three to four inches. Consistent moisture encourages the feeder roots to knit into the native soil.
For the initial seven to ten days, the sod requires frequent, light watering, often two to three times per day, to prevent the sod pieces from drying out. The goal is to keep the top inch of the soil consistently damp but never saturated or standing in puddles. Over-saturation can lead to fungal disease and root rot, which is just as detrimental as allowing the sod edges to dry and shrink.
After the first week, gradually reduce watering frequency while increasing the duration of each session. This tapering encourages roots to grow deeper in search of moisture, transitioning the turf to a more robust, established state. Heavy foot traffic, pet activity, or fertilizer application should be avoided until the sod is firmly rooted and cannot be easily lifted.
Ongoing Routine Maintenance: Mowing and Irrigation
Once established, St. Augustine turf health depends on specific mowing and irrigation practices. The ideal cutting height ranges from three to four inches, which helps the coarse leaf blades shade the stolons and soil, retaining moisture and suppressing weeds. Mowing too short, known as scalping, severely stresses the grass and can damage the thick stolons.
During the active growing season (spring through early fall), the lawn should be mowed often enough to adhere to the one-third rule. This principle dictates that no more than one-third of the leaf blade’s height should be removed in any single session to prevent undue stress. Utilizing a sharp blade is essential for St. Augustine’s coarse texture, as a dull blade tears the grass, leaving ragged edges susceptible to disease.
Shifting to deep, infrequent irrigation is necessary for established turf to promote a strong root system. The goal is to apply one inch of water per week, delivered in one or two long soaking sessions. Watering should only occur when the grass exhibits early signs of drought stress, such as a dull, bluish-green cast or when footprints remain visible on the lawn. Deep irrigation forces roots downward, making the grass more tolerant of high heat and dry conditions.
Nutrient Management and Fertilization Schedule
St. Augustine grass is a heavy feeder that thrives on a consistent supply of nutrients, particularly nitrogen. The annual nitrogen requirement typically falls between two and four pounds of actual nitrogen per 1,000 square feet, with the higher rate reserved for lawns on sandy soils. A soil test determines specific nutrient needs, but a complete fertilizer blend with a nitrogen-phosphorus-potassium (N-P-K) ratio of 3-1-2 or 4-1-2 is generally recommended.
Fertilization should begin in late spring or early summer, after the lawn has emerged from winter dormancy and has been mowed at least twice. Subsequent applications of a slow-release nitrogen formulation should be spaced six to eight weeks apart, continuing through mid-to-late summer. Slow-release products are preferred because they provide a steady supply of nutrients, encouraging uniform growth without the sudden surge that can lead to excessive thatch accumulation.
The final nitrogen application should be timed four to six weeks before the first expected frost to prepare the grass for dormancy without encouraging new growth. St. Augustine prefers a slightly acidic to neutral soil pH (ideally between 6.0 and 7.5), which optimizes the turf’s ability to absorb nutrients. Iron supplements can be used between fertilizer applications to enhance the deep green color without stimulating excessive leaf growth.
Identifying and Treating Common St. Augustine Issues
St. Augustine lawns are susceptible to specific pests and diseases, requiring targeted identification. The Southern chinch bug feeds on the grass by injecting a toxin into the leaf blades, leading to irregular, expanding patches of yellow and brown grass. These damaged areas are often seen first in hotter, drier sections of the lawn, particularly along sidewalks or driveways.
To check for chinch bugs, the float test can be used: a bottomless cylinder is inserted into the soil at the edge of the damaged area and filled with water, forcing the insects to the surface. Controlling chinch bugs begins with proper irrigation and thatch management, but a targeted application of a residual insecticide is often necessary to eliminate an established infestation.
Brown patch, caused by the fungus Rhizoctonia solani, is the most common disease, manifesting as circular patches of dying, brown turf. The disease is often active during periods of high humidity and cool nighttime temperatures, typically in the fall or spring. Cultural controls are the first line of defense, including reducing nighttime watering and avoiding high nitrogen fertilization during peak disease periods.