Dormant creeping bentgrass represents a fascinating paradox within the turf management world. While this cool-season grass is celebrated for its ability to form a dense, carpet-like surface ideal for putting greens, its capacity to enter a state of seasonal dormancy is often misunderstood. This period, typically occurring during the peak heat of summer or the deep chill of winter, is not a sign of decline but rather a sophisticated survival mechanism. Understanding the biology behind this dormancy is the first step in effective stewardship, allowing managers to distinguish between a sleeping giant and a grass plant that is genuinely struggling.
The Science of Summer Dormancy
For creeping bentgrass, summer dormancy is a strategic pause triggered by environmental stress, primarily heat and drought. When soil temperatures consistently exceed 80°F (27°C) and moisture levels drop, the plant slows its metabolic processes to conserve resources. The vibrant green color fades, replaced by a muted gray-green or tan hue as the crown and stolons enter a protective state. This is a survival tactic, halting growth to preserve energy and water reserves deep within the crown, allowing the plant to endure harsh conditions until the environment becomes favorable again.
Identifying Dormancy vs. Disease
One of the most critical skills for a turf manager is accurately diagnosing the cause of brown patches. Dormant creeping bentgrass will exhibit uniform coloration across the affected area and will not pull up easily, as the roots and crowns remain firmly attached. In contrast, disease patches often show irregular edges, a slimy or matted texture, and the grass can be easily lifted. Footprints on dormant turf will leave a temporary impression but will not create deep ruts, whereas stressed turf from disease or compaction will show more immediate damage.
Winter Dormancy and Cold Adaptation
As temperatures drop in late autumn, creeping bentgrass undergoes a similar protective process known as winter dormancy. The plant gradually hardens off, converting starches into sugars that act as a natural antifreeze. This biochemical change allows the grass to survive freezing temperatures that would be lethal during its active growth phase. While the surface may be covered in snow, the crown remains alive, protected by a layer of insulating ice or soil moisture, waiting for the ground to thaw in spring.
Reduced photosynthetic activity conserves energy.
Increased sugar production lowers the freezing point of cell sap.
Stolons may turn brown, but the crown buds remain viable.
Traffic tolerance decreases significantly during this vulnerable period.
Cultural Practices for Managing Dormancy
Managing dormant creeping bentgrass requires a shift in approach rather than a complete abandonment of the turf. During summer dormancy, irrigation should be applied deeply but infrequently to encourage roots to seek moisture below the heat zone, avoiding light daily watering that promotes shallow roots. Fertilization should be avoided, as the plant is not actively growing to utilize the nutrients, and excess nitrogen can exacerbate stress. Mowing height should be raised slightly to provide additional leaf area for photosynthesis and to shade the soil, reducing moisture loss.
Transitioning Out of Dormancy
The return to active growth is a delicate process that requires patience. As temperatures moderate in fall or spring, the plant will naturally break dormancy. To support this transition, a gradual reduction in shade and an increase in air circulation can help warm the canopy. Light aeration and topdressing with sand can alleviate compaction accumulated during the dormant period, ensuring oxygen can reach the crown. Fertilization should be applied cautiously only once consistent growth is observed, using a slow-release formula to avoid shocking the plant.
