Zoysia grass is a popular choice for lawns in warm-season and transition zones due to its dense growth and attractive appearance. Like other warm-season turf varieties, Zoysia enters dormancy when cold weather arrives as a natural protective mechanism. This causes the grass blades to turn a straw-brown or tan color throughout the winter months. Homeowners often wonder about the specific timing of the spring transition, when the lawn returns to a vibrant green.
The Critical Temperature Threshold
The most important factor determining when Zoysia grass wakes up is the sustained temperature of the soil, not the air. Zoysia must sense warmth at the root level before it breaks dormancy and resumes growth. Green-up typically begins when the soil temperature, measured at a four-inch depth, consistently holds at or above 50°F.
While 50°F triggers the initial break from dormancy, active growth requires warmer soil. Full spring transition, where the lawn begins to fill in and grow noticeably, requires soil temperatures to reach 65°F. This explains why lawns often show patchy, uneven greening initially, with the full, uniform color appearing later. Robust growth, which defines the growing season, requires consistent soil temperatures in the 70°F range.
Variables Affecting Spring Timing
The exact date a Zoysia lawn turns green can vary significantly, even between properties in the same neighborhood, due to several localized factors. Geographical location plays a large role, as the speed at which the ground warms is tied to latitude and climate. For example, lawns in coastal areas typically green up weeks before those further inland or in cooler transition zones.
Microclimates within a single yard also influence the timing of green-up. Areas receiving full sunlight warm up faster than shaded sections. Soil temperatures in heavily shaded areas can lag behind sunny spots, delaying the start of the growth cycle.
The composition of the soil affects how quickly it absorbs and retains heat. Well-drained soils, such as sandy loam, warm up faster in the spring, giving the grass a head start. Conversely, heavy clay soils retain more moisture and remain cooler for longer, delaying the spring transition.
Different Zoysia cultivars display variations in their cold tolerance and green-up speed. Varieties like ‘Meyer’ Zoysia are known for their cold tolerance and good spring green-up. Other types, such as ‘El Toro,’ are noted for an earlier spring green-up than older selections.
Initial Care After Green-Up
Once the Zoysia lawn shows signs of greening, maintenance steps help the grass transition smoothly into its active growing season. The first task should be a low mowing pass, set slightly lower than the regular summer height, to remove the dried winter material. Ensure the mower blade is sharp to provide a clean cut and avoid tearing the fragile new growth.
Watering practices should be adjusted as the grass wakes up, moving away from the minimal moisture needed during dormancy. The lawn should receive deep, infrequent watering totaling about one inch per week. This encourages the development of a strong, deep root system, as watering deeply and less often is better than light, daily watering.
Homeowners should resist the urge to apply nitrogen fertilizer immediately upon seeing the first signs of green. Fertilizing too early promotes weed growth and can damage the lawn if a late spring frost occurs. The first application of nitrogen fertilizer should be delayed until the grass is fully out of dormancy and actively growing, typically three to six weeks after the initial green-up.