Fescue is a popular cool-season grass, often used in lawns across the United States transition zone. While it thrives in cooler temperatures, fescue faces significant stress when summer heat arrives. Yes, fescue goes dormant in summer, employing this survival mechanism when faced with prolonged high temperatures and drought. This natural process allows the grass to protect its core structure until favorable growing conditions return in the fall.
The Fescue Dormancy Cycle
Fescue is programmed to slow or halt growth when environmental conditions become unfavorable, particularly during summer. Dormancy is primarily triggered by sustained high temperatures, often above 85 degrees Fahrenheit, and insufficient soil moisture, which induces drought stress. The grass conserves energy by ceasing chlorophyll production, causing the leaf blades to turn a straw-like tan color.
The plant redirects resources away from the shoots and into the crown, the growing point at the base of the plant, and the root system. This defensive strategy allows the grass to survive harsh conditions, as it is not a sign of disease or death. Protecting the crown and roots ensures the fescue can rapidly green up and resume growth once cooler temperatures and adequate moisture return.
Dormant Versus Dead: Identifying the Difference
Distinguishing a dormant fescue lawn from a dead one is a common concern for homeowners seeing brown grass. A simple “tug test” provides a quick diagnosis: gently pull on a handful of the brown grass blades. If the grass resists the pull and stays firmly rooted, it is likely dormant. If the grass comes up easily with little resistance, it has probably died.
Another diagnostic method involves inspecting the grass crown, the central growth point located at the soil surface. In a dormant plant, the above-ground blades are tan or straw-colored, but the crown should still appear firm and possess a faint white or light green color. If the entire plant, including the crown, is brittle, dark brown, or gray, the grass is likely dead and will not recover. Dead grass often appears in distinct patches, while dormancy typically affects the lawn uniformly.
Summer Care for Dormant Fescue
While fescue is dormant, the focus shifts from growth to survival, requiring minimal but targeted care to keep the crown alive. The most important action is to provide a small amount of moisture periodically to prevent the crown from desiccating. A light sprinkling of approximately one-half inch of water every two to three weeks is sufficient to sustain the plant without forcing it out of dormancy prematurely.
During this stressful period, foot traffic should be minimized across the lawn. The brittle, dormant blades are easily damaged, and the plant has limited resources for repair. Mowing practices also need adjustment; raise the deck height to the highest setting or stop mowing completely. Taller grass blades shade the soil, keeping the root zone cooler and reducing heat stress. Chemical applications, such as fertilizers or herbicides, should be avoided until cooler weather arrives in the fall. Applying these during peak summer heat can unnecessarily stress or kill the vulnerable grass.