St. Augustine grass plugs are small, rooted sections of mature turf, typically measuring between 1.5 and 3 inches in diameter, used to propagate a lawn. This method is a cost-effective alternative to installing full sod, allowing the grass to spread and fill in over time. St. Augustine grass spreads aggressively by above-ground runners called stolons, making plugs an efficient way to establish a dense, warm-season lawn. Plugs have established root systems, which promote quicker establishment and healthier growth compared to seeding. This article provides a guide to calculating the quantity of plugs needed for successful turf establishment, alongside the necessary preparation and aftercare steps.
Determining the Number of Plugs Required
The number of St. Augustine plugs needed is determined by the total area of the lawn and the chosen spacing interval, which directly affects the speed of coverage. You must first calculate the total square footage of the planting area by multiplying the length by the width. For irregularly shaped areas, divide the space into smaller, manageable rectangles and then sum their individual areas.
The next step involves selecting the appropriate plug spacing, which balances budget constraints with the desired fill-in time. Closer spacing results in faster coverage, while wider spacing is more economical. Standard recommendations range from one foot apart for the quickest fill-in to 1.5 or 2 feet apart for a more budget-conscious approach. A spacing of 12 inches (1 foot) on center is recommended for optimal growth and fast establishment.
The calculation formula for the total number of plugs is straightforward: divide the total square footage of the area by the square of the spacing interval in feet. For example, if you choose a 1.5-foot spacing, you would divide the total square footage by 2.25. Using a 1-foot spacing requires dividing the area by 1.0, meaning the number of plugs equals the square footage.
For quick reference, here is the approximate number of plugs required per 1,000 square feet based on common spacing choices:
| Spacing Interval | Plugs per 1,000 sq. ft. |
| :— | :— |
| 1.0 foot (12 inches) | 1,000 Plugs |
| 1.5 feet (18 inches) | 444 Plugs |
| 2.0 feet (24 inches) | 250 Plugs |
Essential Site Preparation
Proper ground preparation before planting sets the stage for the plugs to thrive. The first order of business is eliminating all existing weeds and competing grasses, as St. Augustine plugs are vulnerable to competition during their establishment phase. This can be accomplished either manually by removing all vegetation or by using a non-selective herbicide, which should be applied two weeks before planting.
Conduct a soil test to understand the existing nutrient levels and pH balance. St. Augustine grass performs best in soil that is slightly acidic to neutral, ideally within a pH range of 6.0 to 7.5. If the soil test suggests the need for amendments, incorporate organic matter like compost or topsoil to improve drainage and nutrient retention, especially in heavy clay or overly sandy soils.
The planting area should be properly graded to ensure water drains away from structures and to prevent standing water. After incorporating any amendments, the soil surface should be firmed and raked smooth to remove debris, creating an even plane for the plugs. Finally, the soil should be thoroughly watered before planting to ensure it is moist and soft, which facilitates digging and encourages immediate root-to-soil contact.
Establishing and Encouraging Turf Spread
The initial aftercare focuses on keeping the newly planted plugs consistently moist to establish roots. For the first two weeks following installation, the plugs should receive frequent, shallow watering, often daily, to prevent the root systems from drying out. This regular moisture helps the roots settle and begin to grow into the surrounding soil.
After the initial establishment period, typically around two weeks, the watering frequency should be gradually reduced to encourage deeper root growth. The goal is to transition to a schedule that delivers approximately one inch of water per week, factoring in any rainfall, to moisten the soil to a depth of 6 to 8 inches. Deep, less frequent watering promotes a more resilient turf that is better able to withstand drought conditions.
St. Augustine spreads by producing stolons, and fertilization is timed to encourage this lateral growth. About four to six weeks after planting, once the plugs have shown new growth, apply a balanced lawn fertilizer. A formula that includes nitrogen, phosphorus, and potassium is beneficial, with phosphorus being important for root development in new plantings.
Mowing should commence once the plugs are firmly rooted and show vertical growth, typically maintaining a height between 3 and 4 inches. This high cutting height encourages the plant to put energy into lateral spread via stolons rather than vertical leaf growth. Always use a sharp blade and never remove more than one-third of the grass blade height in a single mowing session to avoid stressing the new turf.