Kentucky Bluegrass is a cool-season turfgrass known for its dense, lush appearance and resilience. This resilience is partly due to its survival mechanism called dormancy. Dormancy allows the grass to endure unfavorable conditions by temporarily halting active growth. It is a protective measure that ensures the long-term health of the lawn during periods of environmental stress.
The Critical Temperature for Dormancy
Kentucky Bluegrass typically enters dormancy when environmental conditions become challenging, primarily due to heat and lack of moisture. When soil temperatures consistently rise above 65-70°F (18-21°C) and air temperatures remain consistently above 80-85°F (27-29°C), especially in combination with drought, the grass will begin to go dormant. This response is a physiological adaptation where the grass conserves energy and moisture. The shallow root system of Kentucky Bluegrass makes it less tolerant of heat and drought compared to some other grass types, prompting it to enter dormancy more readily. This is a survival strategy, not a sign of the lawn dying. The grass temporarily shuts down its growth processes to protect its vital parts from extreme conditions.
What Dormancy Means for Your Lawn
When Kentucky Bluegrass enters dormancy, its appearance changes notably, as the grass blades turn brown or straw-colored, giving the lawn a dry, lifeless look. Despite this visual change, the crown and root system of the grass remain alive and intact underground. The browning is a uniform process across the lawn, which differentiates it from dead patches that might appear in distinct spots. Growth ceases as the grass conserves its energy and resources, allowing it to survive extended periods without rainfall or irrigation. A healthy lawn can typically remain dormant for four to six weeks, and sometimes even longer, without suffering significant damage.
Caring for a Dormant Lawn
Managing a dormant Kentucky Bluegrass lawn involves specific practices to ensure its survival and quick recovery. Minimal watering is advised, typically about 0.25 to 0.5 inches every two to four weeks, to keep the crowns hydrated without encouraging green-up. Foot traffic should be avoided on a dormant lawn, as heavy use can damage the turfgrass crowns, potentially hindering recovery. Fertilizing or applying herbicides is generally not recommended during dormancy because the grass is not actively absorbing nutrients, and chemicals may not be effective. The grass will naturally green up again when cooler temperatures return and sufficient moisture becomes available.