How To Protect and Restore your Turfgrass from Summer Stress

Introduction
What is Summer Stress?

Comparison of wilt stress after 3 days of high heat and drought conditions.
Drought vs. Heat Stress:
Heat Stress
When temperatures exceed 60-75°F (the ideal range for cool-season turfgrasses) turf metabolic rate and health begin to decline. Turf may become susceptible to tire track burn (also known as heat tracking) leading to the creation brown spots in specific areas. After some time, turf grass may enter dormancy to conserve energy. When cool-season turf enters dormancy during heat stress, it consumes less water and can stay in this state for up to 4 weeks before the risk of tissue death becomes problematic. Dormant turf is not dead, although it can be hard to tell the difference once dormancy has taken full effect. When dormant, turf can turn brown. It will come out of dormancy and green up with regular watering once temperatures begin to drop.

(Left) Tire track burns left on turf experiencing heat stress.
(Right) Cool-season turf has entered dormancy while a patch of warm-season turf stays green.
High air temperature is not the only factor that contributes to heat stress. Heightened soil temperatures can also be detrimental to turf health. "In a controlled study at Rutgers University, the researchers exposed creeping bentgrass plants to increasing soil temperatures while holding the air temperature constant at 68 °F. Above 70 °F, they observed a decline in root mass, length, and activity, which continued to decline with increasing soil temperature" writes Dr. T. K. Danneberger and Dr. J. R. Street & P. J. Sherratt. When soil temperatures exceed a daily average of 70°F, cool-season turf root mass can be negatively impacted by more than 50%. Cool-season and warm-season turfgrasses perform best at specific temperatures. The key is making sure the soil moisture is adequate. Without moisture in the soil, turf risks drought stress and plant death.
Drought Stress
Drought stress is another major problem for turfgrass varieties. Although warm-season grasses can withstand the heat of summer in most areas when compared to cool-season grasses, both are subject to drought stress and risk going dormant without water. Turf will begin to show signs of drought stress when the amount of water lost in transpiration is greater than the amount of water available. Drought stress is most noticeable on slopes as well as turf that is established in shallow or poor soil. The quality of the soil is key to the quality of the turf. Lack of water (rainfall or irrigation) can lead to a decrease in growth due to a decrease in photosynthesis and plant respiration and an increase in plant temperature. Put together with the already high summer temperatures, turf that undergoes drought stress is at risk of death. Knowing how to spot the beginning stages of drought stress is important to keep your turf healthy.

A loss in elasticity in the plant walls of turf during drought will result in footprints lasting several minutes to hours on turf before bouncing back up.
Prevention
Recovery
In Summary
For professional fertilizers, soil amendments or biologicals like AMP-XC , humic or sea kelp products, visit Turf Care Supply’s online Product Catalog
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