Zoysia grass is a warm-season turf known for its dense growth, fine texture, and exceptional tolerance to heat and foot traffic. While sodding or planting plugs offers immediate results, seeding is often the preferred, cost-effective method for covering large areas. Establishing Zoysia from seed requires attention to specific conditions, especially timing and moisture management, which differ significantly from cooler-season grasses. This guide outlines the necessary steps for establishing a vibrant Zoysia lawn.
Preparing the Ground for Zoysia
The best time to sow Zoysia seeds is when the soil temperature consistently registers between 65°F and 70°F, typically in late spring or early summer. Zoysia requires these warm temperatures for germination. Use a soil thermometer to check the temperature at a depth of 2 to 4 inches, as this is more reliable than relying on air temperature.
Before seeding, all existing vegetation, including previous turf and weeds, must be completely removed, often requiring a non-selective herbicide or mechanical stripping. Conducting a soil test is highly recommended to determine the existing pH and nutrient profile. Zoysia grass prefers a slightly acidic to neutral pH range of 5.8 to 7.0, and amendments like lime or sulfur should be incorporated based on test results.
The soil should be loosened to a depth of 4 to 6 inches, either through tilling or core aeration, to improve drainage and allow for root penetration. After amending and loosening the soil, the entire area must be finely graded to ensure a smooth, level surface. Proper grading prevents water from puddling after irrigation, which can wash away seeds and create inconsistent growth.
Applying the Seed
Varieties like Zenith and Compadre are common seeded cultivars of Zoysia japonica. Since Zoysia seed is relatively small, it is helpful to mix the seed with an inert material, such as sand or fine dry topsoil, to ensure even distribution during application.
The seed should be spread using a broadcast or drop spreader at a rate of approximately 1 to 2 pounds per 1,000 square feet for a new lawn. Applying half the seed while walking in one direction and the remaining half perpendicular to the first pass maximizes coverage uniformity. After spreading, the seed must achieve good contact with the soil, which is accomplished by lightly raking it into the top eighth of an inch of soil or by using a lawn roller.
Immediately after seeding and lightly covering, apply a high-phosphorus starter fertilizer across the entire area. Starter fertilizers are formulated with a high middle number in the N-P-K ratio (e.g., 10-18-10 or 18-24-12) to promote the deep, strong root development necessary for successful establishment.
The Critical Germination Phase
The period immediately following planting requires constant moisture for the seeds to germinate successfully. Zoysia germination is slow, typically taking between 14 and 21 days under ideal conditions, though it can take longer if temperatures fluctuate. The goal during this time is to keep the top quarter-inch of soil continuously moist, but never saturated, to prevent the seeds from drying out.
Consistent moisture often necessitates light, frequent watering sessions, sometimes three to five times per day, particularly during the warmest part of the day. Using short bursts of irrigation prevents water runoff, which could displace the seeds and wash away the starter fertilizer. Missing even one day of watering during this initial sprouting period can cause the seedlings to desiccate and die.
Once the majority of the seeds have sprouted and the new grass blades are visible, gradually reduce the watering frequency while increasing the duration of each session. This transition encourages the young roots to grow deeper into the soil, preparing the plant for the less frequent watering schedule of a mature lawn. Avoid heavy foot traffic throughout this establishment phase, as it can compact the soil or damage the new growth.
Long-Term Establishment and Mowing
Delay the first mowing of a new Zoysia lawn until the grass blades reach a height of 3 to 4 inches. The initial cut should only remove the top third of the blade, a standard rule for turfgrass mowing. Mower blades must be sharp to avoid tearing the new shoots, and maintaining a slightly higher cut of 2 to 2.5 inches for the first few months allows the grass to develop an extensive root system.
Approximately six to eight weeks after planting, once the grass is visibly establishing itself, shift the fertilization program away from the high-phosphorus starter formula. The lawn will benefit from a maintenance fertilizer that is higher in nitrogen to support continued leaf and lateral growth. This application helps the slow-growing Zoysia spread and form the dense turf it is known for.
Weed management in a young Zoysia lawn requires careful consideration because pre-emergent herbicides can inhibit the growth of the desirable grass seedlings. Pre-emergent products, which prevent seeds from sprouting, should not be applied until the Zoysia is fully established, which may take several months. In the interim, control any weeds manually or with post-emergent herbicides specifically labeled as safe for use on young Zoysia turfgrass.