The Carolinas are a great place to live. We live in a transition zone that can support both warm and cool season grasses. While warm season grasses grow best in the summer, cool season grasses like fescue maintain a green color throughout the winter. The summer months can be tricky for fescue turf. Heat stress is one of our hardest battles we face with this turf type.
Fescue turf has an optimum growth temperature between 60 to 75 degrees. The hot temperatures of summer can cause heat stress. This is why the beautiful fescue lawn that you see in late winter/early spring may start to look spotty in summer. In fact, when temperatures reach 90 degrees and above, fescue will go dormant (meaning the grass stops growing to conserve energy until better conditions arrive). All this is completely normal for cool season turfgrasses. It is just too hot for them to grow optimally in the summer months in the south.
The problem comes with continually high temperatures. Eventually, the string of 90 plus degree weather with no break can cause roots to die back, resulting in a loss of large amounts of turf. We've already had over 20 days of weather topping out over 90 degrees this spring/summer. And it's not even July yet! What can you do to help your fescue turf fight heat stress?
- First of all, the deeper and more established your roots are the longer your fescue can take the heat. Disease or insect infestation can damage root health, making your lawn more susceptible to heat stress. There are preventative sprays you can put on your lawn to guard against these types of issues. Soil tests are also useful to identify problems with the soil that may be hindering root growth.
- At AA Tex Lawn, we mow fescue above 3 3/4 inches in the summer to help reduce stress. We want to avoid breaking the grass blade off at the ground, which could damage the plant.
- Because of the hot weather we've had this year, we have moved many of our clients to a 10 day mowing schedule. This is a way to keep from overtaxing the grass that is already close to dormancy by the heat. Stressed turf does not respond well to foot or mower traffic.
- A deep long watering can help delay heat stress, but essentially this is a temperature issue, not a water issue. With continued extreme temperatures, watering and irrigation will not overcome the excessive heat.
Remember, dormancy is normal for fescue turf. It is a survival tactic cool season turfs use to get through hot weather until prime growing conditions return. Our job as landscapers is to do what we can to help the dormant fescue recover quickly when temperatures lower. The goal is to avoid injuring the roots so that as much turf will recover as possible when the cooler weather returns in the fall. Barring any radical temperature shifts in the fall, fertilization and overseeding should help re-populate areas that are bare because of heat stress. Mother Nature likes to throw us curve-balls. Our job is to do preventative maintenance by making your lawn as healthy as it can be and fight the battle against the weather. If your lawn is a battlefield, together we'll win the war!
