Bermuda grass is a warm-season turf known for its aggressive, spreading growth habit and resilience, making it a popular choice for thick, durable lawns. Reseeding an existing Bermuda lawn is an effective way to improve density and fill in bare patches, but success depends on precise timing and preparation.
Preparing the Area for Optimal Germination
The most important factor for reseeding success is ensuring the soil temperature consistently exceeds 65–70°F, which typically occurs in late spring through early summer. Planting too early risks poor germination and lost seed, as Bermuda grass requires significant warmth to sprout and grow. Soil temperature, not air temperature, is the accurate measure to track for this project.
Before spreading seed, the existing turf must be managed to expose the soil surface, allowing sunlight and water to reach the new seeds. This begins with “scalping,” which involves mowing the existing lawn at the lowest safe setting (0.5 to 1 inch). Bag the clippings to remove the dead grass and debris, which would otherwise block new seedlings from contacting the soil.
Once the area is scalped, consider dethatching or lightly scarifying the surface to expose bare soil. For small areas, a hard rake is sufficient, but larger lawns require a power dethatcher or vertical mower. This creates shallow grooves where the seed can settle and make firm contact with the soil. Applying a starter fertilizer, rich in phosphorus, provides necessary nutrients for young root development during establishment.
Applying the Seed and Ensuring Soil Contact
Selecting hulled Bermuda grass seed is important because the removed outer coat allows water to enter more quickly, promoting faster, uniform germination. The standard seeding rate for overseeding or establishing a new lawn is between 2 to 3 pounds of seed per 1,000 square feet. Calculating the area accurately ensures you do not over-seed, which can lead to overcrowding and weak stands of grass.
To achieve uniform coverage, a broadcast spreader should be used, and the seed should be applied in a cross-hatch pattern. This technique involves spreading half the calculated seed rate walking in one direction (e.g., north to south) and the remaining half walking perpendicularly (e.g., east to west). This two-pass method minimizes the risk of streaking and ensures the entire area receives the correct amount of seed.
Firm seed-to-soil contact is necessary after spreading. Lightly rake the area to work the seed into the top 1/8 inch of soil, or use a lawn roller to press the seed directly onto the prepared surface. A very thin layer of top dressing, such as peat moss or a light compost, can be applied to help retain moisture, but a heavy layer should be avoided as it can inhibit germination.
Managing Water and Maintenance During Establishment
The establishment phase immediately following seeding requires a rigorous watering schedule. The top 1/2 inch of soil must be kept consistently moist until germination occurs, which typically takes between 7 and 21 days for Bermuda grass. This often requires frequent, shallow watering cycles, sometimes three to five times per day, to prevent the tiny seeds from drying out.
Once the new seedlings have emerged and reach about 1 to 1.5 inches in height, the watering schedule should be gradually adjusted. The goal is to reduce the frequency of watering while increasing the duration, encouraging the new roots to grow deeper into the soil in search of moisture. This transition is important for developing a drought-tolerant and robust root system.
The first mowing can generally take place when the new grass reaches a height of approximately 2 inches. It is essential to use a sharp mower blade and set the cutting deck high for this initial cut, removing no more than one-third of the blade height to avoid stressing the fragile young plants. Avoid applying broadleaf or pre-emergent herbicides until the new lawn is fully established (after at least three mowings or 30 days), as herbicides can kill or severely injure the young grass.