Bermuda grass is a warm-season turf, actively growing during the hottest months of the year. When temperatures drop, it enters dormancy. This survival mechanism conserves energy and resources within its root system, resulting in the characteristic browning or straw-like appearance of the lawn. The grass is not dead; it has simply stopped producing chlorophyll, the pigment that gives the blades their green color, until warmer conditions return. This resting period allows the lawn to withstand cold stress and ensures long-term vigor when the growing season begins again.
The Soil Temperature Threshold
The exact moment Bermuda grass exits dormancy is not determined by a calendar date but by a specific, sustained environmental condition. The primary trigger for green-up is when the soil temperature, measured at a 4-inch depth, consistently reaches 60 to 65 degrees Fahrenheit. This sustained warmth allows the plant’s metabolic processes to resume active growth and chlorophyll production.
Air temperature is a less reliable indicator than soil temperature for this transition. Soil retains heat more effectively and changes temperature more slowly than the air, providing a more stable measure of when the roots are warm enough to support new growth. While warm days can temporarily raise air temperatures, the Bermuda grass will not fully break dormancy until the underlying soil mass has reached and maintained the necessary thermal threshold. This explains why the timing of spring green-up is highly variable, shifting earlier or later each year based on local climate and specific weather patterns.
Preparing the Lawn Before Spring Growth
Even while the lawn is dormant, homeowners can take actions to accelerate spring revival. The most effective step is scalping, which involves mowing the lawn down to a very low height, often removing 40 to 60 percent of the dead canopy. Removing this layer of dead material allows sunlight to penetrate directly to the soil surface, which helps warm the ground more quickly and can hasten green-up by up to two to three weeks.
However, care must be taken during scalping to avoid cutting down to bare soil, which creates an ideal environment for weed germination. Following scalping, applying a pre-emergent herbicide is recommended for weed control. This herbicide should be timed to coincide with soil temperatures reaching 55 degrees Fahrenheit, just before the 60-65 degree window for green-up. Applying the product at this time prevents the seeds of common spring weeds, such as crabgrass, from germinating and competing with the newly emerging turf.
Early Season Maintenance After Green-Up
Once the Bermuda grass has broken dormancy and is showing sustained green color, maintenance activities shift to supporting the new turf. The first application of nitrogen fertilizer should be delayed until the lawn is 50% to 75% green and the threat of a late frost has passed. Fertilizing too early encourages tender shoot growth that is vulnerable to damage from an unexpected freeze, and can also promote top growth at the expense of root development.
For this initial feeding, a slow-release nitrogen fertilizer is recommended to provide steady nutrition as the grass enters its peak growing season. As the turf begins to fill in, the mowing height should be adjusted upward to the standard maintenance height, typically between 1 and 1.5 inches for an established lawn. Finally, a consistent watering routine of about one inch per week, including rainfall, should be established to support the robust growth of the newly emerged turf.