Bermuda grass is a warm-season turf, meaning it thrives in the heat of Texas summers but must adapt to survive the cooler months. This adaptation is a natural, protective state called dormancy. When the grass enters dormancy, its metabolism slows significantly, shifting its energy from producing green blades to protecting its underground root system and crowns. This process allows the plant to conserve the resources it needs to emerge healthy and robust when warm weather returns.
Environmental Signals That Initiate Dormancy
The transition into dormancy is not a sudden event but a gradual response to two primary environmental signals that occur in the fall. The first is a sustained drop in air and soil temperatures, which is the most definitive trigger for Bermuda grass. Growth activity slows substantially when soil temperatures consistently fall below 60°F, and the grass typically enters full dormancy when temperatures remain around 50–55°F.
The second signal is the decreased photoperiod, or the reduction in daylight hours. This shorter day length signals that the active growing season is ending. The grass responds by slowing its photosynthetic processes and reducing the production of chlorophyll, which prepares it to survive winter. The first hard frost event often serves as the final trigger, causing any remaining green tissue to turn brown quickly.
Regional Dormancy Timing in Texas
The exact timing of dormancy in Texas varies considerably due to the state’s vast size and diverse climate zones. Generally, Bermuda grass begins to enter dormancy in the late fall and remains in this state until early spring, typically from November through March. Once dormant, the lawn changes from a vibrant green to a straw-like, tan or light brown color as the green leaf tissue dies back.
Homeowners in North Texas, including areas like Dallas and Amarillo, see the earliest onset of dormancy. Cooler air masses arrive sooner, causing soil temperatures to drop quickly, often pushing the grass into dormancy between late October and mid-November. Moving south to Central Texas, encompassing cities such as Austin and San Antonio, the milder climate delays the onset until mid-to-late November.
The Gulf Coast and South Texas regions, including Houston and the Rio Grande Valley, experience the latest and sometimes incomplete dormancy. Winters here are often mild enough that the grass may not go fully dormant until December or January, or it may only enter a semi-dormant state. In these areas, the grass may appear thin or off-color rather than completely straw-brown, making the timing highly dependent on the severity of the winter season.
Maintaining the Lawn During Dormancy
Although the grass is not actively growing during dormancy, care is necessary to maintain the health of the underground root system. Watering must be significantly reduced but not completely stopped, as the root crowns can still dehydrate during dry winter periods. Deep, infrequent watering, such as once every four weeks if no substantial rain occurs, is sufficient to prevent the roots from drying out.
Mowing can largely cease once the lawn is fully dormant, as there is little to no leaf growth. Limiting traffic on the brown, dormant lawn is important because the grass is brittle and cannot recover from wear and tear, which can lead to patchy areas in the spring. If temperatures remain unusually warm and a small amount of growth occurs, mowing should only be done to trim the grass and never to scalp the lawn.
Fertilization practices change once dormancy is imminent, with the focus shifting from growth promotion to root protection. Nitrogen application, which stimulates green top growth, must be stopped in the fall. This avoids encouraging tender growth that cold weather could damage. Instead, a high-potassium, low-nitrogen fertilizer should be applied in the early fall to help the grass build strong, resilient root systems before the cold weather arrives.
The dormant period is the ideal time to apply pre-emergent herbicides to control cool-season weeds that thrive when the Bermuda grass is inactive. These herbicides work by creating a barrier that stops weed seeds from germinating throughout the winter. This targeted application helps ensure that the Bermuda grass has less competition for water and nutrients when it breaks dormancy and begins to actively grow again in the spring.