When a lawn turns yellow or straw-brown, homeowners must determine if the grass is merely taking a break (dormancy) or if it is permanently damaged (dead). This discoloration signals a serious stress event. Distinguishing between temporary dormancy and irreversible plant death is crucial, as the correct diagnosis is the first step toward effective lawn recovery.
How to Tell Dead Grass from Dormant Grass
The physical condition of the grass is the most reliable indicator of its state. The easiest field diagnostic is the “tug test,” where a small handful of the discolored grass is gently pulled upward. If the grass is merely dormant, its roots remain firmly anchored in the soil and resist the pull, indicating a still-living plant. Conversely, if the blades pull out easily with little to no resistance, the root system has failed, and the grass is dead.
A secondary check involves examining the crown, which is the white, bulbous growth point at the base of the grass blade near the soil line. Carefully inspect the crown of a few pulled-up blades. A crown that retains a white, creamy, or slightly green color holds the living tissue and energy reserves necessary for regrowth. If the crown is completely brown, brittle, or gray all the way through, the grass is no longer viable and cannot recover on its own.
Common Reasons Grass Enters Dormancy
Dormancy is a natural, protective response that allows the grass plant to survive conditions that would otherwise kill it. The grass metabolizes slower and redirects energy reserves from the leaf blades to the crown and roots. Severe drought is a primary trigger, as the plant conserves moisture by halting active growth and turning the leaf blades brown.
Extreme heat often works alongside drought to induce this resting state, particularly for cool-season grasses like fescue, which may enter summer dormancy when temperatures consistently rise above 85°F. Warm-season varieties like Bermuda or Zoysia also experience seasonal dormancy when soil temperatures drop below 55-60°F during the winter.
When Yellow Grass Signals a Serious Problem
Not all yellowing is a sign of dormancy; localized yellow or brown patches often signal a serious underlying issue. Fungal diseases, such as brown patch or dollar spot, typically appear as circular or irregular dying areas. These diseases thrive in high humidity and moisture, and can rapidly destroy turf.
Insect infestations, including grubs and chinch bugs, also cause yellowing by attacking the root system or sucking the life from the grass blades. Grubs feed on the roots, causing the grass to turn yellow and wilt, often allowing affected sections of turf to be rolled back like a carpet. Nutrient issues, most often a lack of nitrogen, cause a uniform pale-green or yellow tint across the entire lawn. Iron chlorosis, an iron deficiency, creates a similar yellowing, particularly on new growth.
Chemical injury often results from the misuse of fertilizers or herbicides. Over-application of fertilizer can “burn” the grass with excess salts, creating irregular yellow or brown spots. Mechanical damage like scalping, which occurs when the grass is cut too short, removes too much of the photosynthetic blade, leading to temporary yellowing until the plant recovers.
Strategies for Recovery and Prevention
The approach to recovery depends entirely on the initial diagnosis. If the grass is confirmed to be dormant, the primary action is patience, as the grass will green up once favorable temperatures and consistent rainfall return. If drought conditions persist, a deep, infrequent watering of about half an inch every three to four weeks can keep the crown hydrated without encouraging active growth.
For grass that is confirmed dead or dying from a specific ailment, targeted treatment is necessary. Fungal diseases may require a broad-spectrum fungicide, while grub infestations demand a curative insecticide treatment. If a nutrient deficiency is identified, a soil test should guide the application of the correct fertilizer or soil amendment. Dead patches must be repaired by reseeding or installing new sod.
Prevention involves adopting proper cultural practices to strengthen the turf’s natural defenses. Watering deeply and infrequently encourages deep root growth, making the grass more resistant to drought and heat stress. Maintaining the correct mowing height and conducting annual soil tests to balance nutrients will help ensure the lawn remains healthy and resilient.