St. Augustine grass is a warm-season turf known for its dense, carpet-like growth, making it a popular choice for lawns in warmer climates. To establish a new lawn, plugs—small sections of mature sod—are used for propagation, allowing the grass to spread and fill the area. The time required to achieve a uniform, fully covered lawn varies significantly based on environmental factors and maintenance practices. Understanding the expected timeline and the elements that affect it is key to a successful lawn transformation.
The Timeline for Full Coverage
Achieving a dense lawn from St. Augustine plugs occurs in distinct stages. Initial establishment, where the plugs anchor into the soil, typically takes four to six weeks. During this period, the grass focuses its energy on root development rather than lateral spread.
Once established, the grass produces above-ground runners, known as stolons, which are responsible for lateral spread. This new growth is often visible within one to two months as the runners creep across the bare soil. Closer plug spacing results in faster coverage time.
Under ideal growing conditions and consistent care, St. Augustine plugs can spread to fill a lawn within six to twelve months. While coverage can occur faster if plugs are planted very closely, this six-to-twelve-month timeframe is a more realistic expectation. The timeline is a function of the grass’s natural vigor and the environment.
Essential Factors Influencing Spread Rate
The speed at which St. Augustine plugs spread is influenced by several environmental conditions. Temperature is a primary driver, as this warm-season grass grows fastest when daytime temperatures range from 80°F to 95°F. Planting during late spring and early summer allows the grass to leverage warm weather for faster root and stolon development.
Soil quality also plays a substantial role. Well-draining soil with a pH range between 6.0 and 7.5 is preferable for optimal growth. Poorly draining or compacted soil impedes root growth and limits the stolons’ ability to anchor.
Conducting a soil test provides insights into nutrient levels, allowing for amendments that create a more favorable environment for the plugs.
Sunlight is another determinant of spread rate. Although St. Augustine is shade-tolerant, it requires a minimum of four to six hours of direct sunlight daily to support vigorous growth. Growth will be noticeably slower in heavily shaded areas.
Finally, the specific cultivar chosen affects the spread rate. Varieties like Floratam or Palmetto are known for their aggressive spreading habits. Selecting a faster-spreading variety can reduce the overall coverage timeline.
Post-Planting Care for Maximum Spread
The maintenance routine following planting encourages the maximum spread rate. A targeted watering regimen is crucial immediately after planting, requiring thorough soaking to help the roots settle and remove air pockets. For the first two to three weeks, the plugs need frequent, often daily, watering to keep the soil consistently moist until the root system is established.
After establishment, reduce the watering frequency, transitioning to a deep, infrequent schedule that encourages deep root growth. Provide about one inch of water per week, factoring in rainfall, to promote healthy growth. Deep watering encourages the grass to seek moisture deeper in the soil, supporting the energy needed for stolon production while avoiding overwatering and fungal issues like brown patch.
A proper fertilization schedule delivers the nutrients required to fuel lateral growth. Apply a balanced starter fertilizer shortly after planting to stimulate root development. Follow this with a nitrogen-rich fertilizer application four to six weeks later, and then every six to eight weeks during the active growing season. Nitrogen is particularly important as it drives the vegetative growth and production of new stolons that spread across the bare ground.
Mowing practices directly influence lateral spread. St. Augustine should be mowed at a high setting, typically between 2.5 and 4 inches. Maintaining this height encourages the grass to grow laterally rather than vertically. Avoiding scalping—cutting off too much of the blade—prevents stress that would divert energy away from spreading.
Weed control is also important, as competing weeds slow down coverage by stealing water, nutrients, and sunlight from the newly planted plugs. Applying a pre-emergent herbicide labeled safe for St. Augustine plugs about two to four weeks after planting helps manage weed germination without damaging the young grass.