St. Augustine grass is a favored turfgrass choice across Texas, offering a dense, dark-green lawn that tolerates intense heat and moderate shade. Successfully maintaining this grass requires specific cultural practices tailored to the Texas climate, including high summer temperatures, fluctuating humidity, and often-heavy clay soils. A focused approach to mowing, feeding, and especially watering helps the turf build the resilience necessary to thrive. This management strategy must be consistent, focusing on prevention to mitigate common pests and diseases.
Routine Cultural Practices: Mowing and Fertilization
A consistent mowing height is one of the simplest yet most important aspects of St. Augustine grass care, directly impacting the health of the root system. Maintain the grass blades between 2.5 and 4 inches, preferring taller heights during summer heat to encourage deeper roots and provide shade to the runners. Never remove more than one-third of the total blade height in a single session, which typically means mowing weekly during the peak growing season.
The fertilization schedule should align with the grass’s active growth period, which runs from late spring through early fall. The first application should occur after the lawn has fully greened up and mowed at least twice, signaling the end of dormancy. Use a slow-release, high-nitrogen fertilizer, often with a 3-1-2 or 4-1-2 ratio, to provide a steady supply of nutrients.
Subsequent applications can be made in mid-summer and early fall, approximately every six to ten weeks, to sustain growth. Avoid fertilizing with nitrogen within four to six weeks of the first expected frost date, as this encourages new growth vulnerable to cold damage. The total annual nitrogen applied should not exceed four pounds per 1,000 square feet.
Strategic Water Management in Texas Heat
Proper irrigation is the most important factor for St. Augustine survival during the Texas summer, requiring a deep and infrequent watering schedule. The goal is to soak the soil to a depth of six to eight inches per session, encouraging the roots to grow downward and increasing drought resistance. This deep soak typically requires applying about one to 1.5 inches of water per week, usually spread across just one or two days.
Watering should occur in the early morning, ideally between 4 a.m. and 8 a.m., to minimize evaporation loss from intense daytime heat. Morning watering also allows the grass blades to dry completely before evening, a crucial practice that reduces the prolonged leaf wetness favoring fungal diseases like Brown Patch. Apply water only when the grass shows the first specific signs of drought stress.
Visual cues for watering include the grass blades folding in half lengthwise, a mechanism the turf uses to conserve moisture. The loss of turgor pressure is another reliable sign, identified through the “footprinting” test, where footprints remain visibly compressed for ten to fifteen seconds or more. Following these signs, rather than a fixed calendar, trains the roots to seek deeper soil moisture.
Managing Pests and Diseases Specific to the Region
St. Augustine grass in Texas is susceptible to specific pests and fungal diseases that require targeted intervention. The southern chinch bug is a major insect pest, thriving in hot, dry conditions, often near sidewalks and driveways. Infestations are characterized by expanding, irregular patches of browning grass that fail to recover after watering, sometimes surrounded by a yellow or orange halo.
To confirm chinch bug activity, check the edges of the damaged area for the small, black-bodied, white-winged adults or the red-colored nymphs. Treatment involves applying a labeled insecticide to the affected patches and the surrounding turf, ensuring the product penetrates the thatch layer. Watering the area before applying a liquid insecticide helps carry the chemical down to where the insects are feeding.
Fungal threats include Brown Patch, most active in the mild, wet conditions of spring and fall, and Take-All Root Rot (TARR), a perennial soil-borne issue. Brown Patch presents as circular patches of thin, light-brown turf, sometimes with a distinctive “smoke ring” of darker grass at the perimeter. Curative treatments rely on fungicides containing active ingredients like azoxystrobin or propiconazole, often requiring rotation to prevent resistance.
Take-All Root Rot is diagnosed by the yellowing of the leaf blades and the presence of blackened, rotten root systems that pull easily from the soil. The most effective treatment for TARR is to topdress the affected area with sphagnum peat moss, applying approximately one 3.8 cubic foot bale per 1,000 square feet. The low pH of the peat moss creates a hostile environment for the fungus, helping the grass recover.