St. Augustine grass is a popular warm-season turf. When installing new St. Augustine sod, the initial watering regimen is the most important factor determining success. The grass is highly vulnerable to desiccation until it can grow new roots into the native soil. This requires a managed, multi-phase watering schedule that evolves from keeping the sod saturated to encouraging deep root growth.
Immediate Saturation: The First 48 Hours
New St. Augustine sod requires immediate and deep saturation to minimize transplant shock. The primary goal is to soak the underlying soil to a depth of at least four to six inches. This creates a saturated moisture reservoir that the new root system can quickly access. Apply enough water so the ground feels noticeably soggy, confirming penetration into the subsoil.
During the first 48 hours, the sod must be kept continuously wet, especially in hot or windy weather. This requires multiple, short watering cycles throughout the day, possibly two to six times, for five to 15 minutes per session. This frequency is necessary because the shallow roots cannot yet draw moisture from the deeper soil.
Check the seams and edges of the sod pieces constantly, as these areas are the most prone to rapid drying. If the sod loses moisture, the pieces can contract, creating visible gaps and causing the edges to turn a straw color. Targeted hand-watering may be required for these vulnerable spots to ensure uniform moisture.
The Rooting Phase Schedule (Days 3 through 14)
After the initial shock, the watering strategy shifts to encouraging new root growth into the native soil. For the next two weeks, keep the upper layer of the sod consistently moist. Frequency begins to slightly decrease while duration is maintained or slightly increased. This phase typically involves watering twice per day—morning and late afternoon—to sustain the shallow roots.
Watering sessions should be short, between 10 and 20 minutes, because the shallow roots can only absorb a limited amount of water. This frequent, brief watering maintains the ideal moist environment without creating a waterlogged condition that could lead to fungal disease or root rot.
As this period progresses, the sod should start to “knit” to the soil. Check this by gently lifting a corner; resistance indicates roots are establishing. By the end of the second week, reduce watering frequency to a single daily session, increasing the duration to 20 to 30 minutes. This reduction in surface moisture encourages the roots to search downward for water.
Transitioning to Deep Watering (Weeks 3 and Beyond)
Starting around the third week, transition from high-frequency surface watering to infrequent, deep watering. The objective is to train the new roots to grow deeply into the soil profile, which builds drought resistance. Achieve this by gradually reducing the frequency of irrigation while increasing the duration of each watering session.
Move the schedule from daily watering to every other day, and then to two or three times per week, with sessions lasting 30 to 45 minutes. This extended duration ensures water penetrates six inches or more, creating a deeper moisture zone that pulls the roots downward. Shallow, frequent water will cause a weak, shallow root system susceptible to heat stress and drought.
By the end of the first month, the sod should be rooted enough to withstand several days between watering cycles, depending on the climate. The long-term goal for established St. Augustine grass is approximately one inch of water per week. Watering deeply and infrequently ensures robust roots and maintains the turf’s vibrant color.
Assessing Moisture Needs and Tool Selection
The most reliable way to gauge the sod’s moisture needs is by physically checking the soil rather than relying on a timer. Gently lift a corner of the sod; the soil underneath should be damp, similar to a wrung-out sponge, but never soupy. Another effective method is pushing a screwdriver or soil probe into the grass; easy penetration to four to six inches indicates adequate moisture.
Observing the grass blades provides clues: a blue-gray tint, wilting, or visible footprints indicate drought stress and an immediate need for water. Monitoring the watering system coverage is important, as sprinklers frequently miss corners or areas near hardscapes, requiring supplemental hand-watering. Use a rain gauge or tuna can to measure irrigation delivery and prevent over- or under-watering.
Monitor for runoff during deep watering phases, which suggests the soil cannot absorb the water quickly enough. If runoff occurs, break the watering session into multiple, shorter cycles separated by a brief pause. This allows the water to soak in fully, ensuring moisture reaches the desired root depth without waste. Hand-held nozzles or oscillating sprinklers are effective tools for consistent, uniform coverage across the entire sodded area.