St. Augustine grass is a warm-season turf known for its distinct blue-green color and broad, flat leaf blades, which create a dense, carpet-like lawn. This grass variety spreads vigorously by above-ground runners, called stolons, which allow it to establish quickly in warm, humid climates. Since St. Augustine grass rarely produces viable seeds, using plugs is a common and economical method for establishing a new lawn or repairing large bare areas. Plugs are small, rooted sections of mature sod, typically measuring a few inches across, that offer a faster establishment time than seeding while being significantly more cost-effective than laying full sod.
Preparing the Planting Area
All existing vegetation, including weeds, old grass, and debris, must be completely eradicated, as competition for water and nutrients will severely hinder the plugs’ ability to spread. Non-selective herbicides can be applied about two weeks prior to planting, or all existing growth can be removed manually. Ensure the root systems are also pulled out during manual removal.
Loosen the soil to a depth of at least three to four inches using a tiller or garden fork to improve aeration and drainage. St. Augustine grass thrives in well-draining soil with a pH level ranging from 6.0 to 7.5. If a soil test indicates poor quality, incorporate organic matter like compost or a loam-based topsoil mix to enhance fertility and structure. Planting should occur in late spring or early summer (generally April through May) when daytime temperatures consistently range between 80°F and 95°F.
The Process of Planting Plugs
Begin by thoroughly watering the prepared soil until it is saturated; this makes digging easier and provides immediate moisture to the root systems. Use a trowel or a specialized plug planting tool to dig holes that are slightly wider than the plug’s root ball and approximately two to four inches deep.
The recommended distance between plugs is typically 12 to 18 inches, with closer spacing encouraging faster fill-in, while wider spacing is more economical but requires more time for the lawn to fully establish. Place each plug into its hole, making sure the top of the grass and soil is perfectly level with the surrounding grade. Planting the plug too deep will bury the crown and stolons, preventing spreading, while planting it too high will expose the roots to drying air.
After placement, firm the soil around the edges of the plug with your hands to remove any air pockets that could dry out the roots. Ensure good soil-to-root contact so the plug can begin drawing moisture and nutrients from the surrounding ground. Once all plugs are installed, apply a starter fertilizer high in phosphorus to stimulate vigorous root growth before the initial heavy watering.
Immediate Post-Planting Care
Immediately after planting, water the entire area heavily to settle the soil, eliminate any remaining air pockets, and reduce transplant shock. For the first week, a frequent, shallow watering schedule is necessary, often requiring two to three short applications per day to keep the plugs and the surrounding soil consistently moist.
The primary goal during this initial phase is to prevent the small root systems from drying out, which requires more attention during midday heat. During the second and third weeks, gradually reduce the watering frequency to once a day, but increase the duration to encourage roots to reach deeper into the soil. Avoid waterlogging the area, as saturated conditions can lead to fungal diseases and root rot. Strictly limit foot traffic during this establishment period to prevent the newly set plugs from being dislodged or damaged.
Encouraging Spreading and Establishment
Once the plugs are firmly rooted, the focus shifts to encouraging the stolons to spread across the bare ground. After approximately four to six weeks, the first application of a nitrogen-heavy fertilizer can be made, as nitrogen is the nutrient that drives the shoot and stolon growth necessary for horizontal expansion. Subsequent fertilization should follow every six to eight weeks throughout the active growing season, always according to soil test recommendations.
Wait to perform the first mow until the grass blades reach a height of at least three to four inches, and then set the mower to the highest possible setting. Maintaining a high cut (typically three to four inches) promotes a deeper root system and allows the grass blades to shade the soil, which helps suppress weed growth and conserve moisture. As the plugs begin to connect, transition watering to a deep, infrequent schedule, supplying about one inch of water per week to foster drought-resilient root growth.