Protecting Your Lawn During a Heatwave

High temps and dry weather: perfect for beach days, backyard barbecues and Sunday afternoon picnics. But for your lawn, it’s a different story. Whether you have cool-season or warm-season grass, extended periods of high temperatures can take a toll on your lawn. This is because the intense heat and lack of moisture can stress the grass, leading to a lawn that appears discolored, feels rough and exhibits poor growth. 

Since you can’t control the weather, you may be wondering what you can do to protect your grass during a heat wave. Here, we’ll get into the nitty-gritty of what heat can do to your lawn and the steps you can take to counteract the potentially damaging effects of hot, dry weather. Plus, you’ll learn about the TruGreen® lawn care services that can help keep your lawn healthy and happy — throughout the summer and beyond. 

Heat stress, as you could probably guess, occurs when your grass gets too hot for too long, which occurs during extreme temperatures in the 90s (or above). Mitigating factors for how quickly heat stress might occur include humidity levels, your lawn’s natural shade, irrigation, the overall health of your lawn, and your watering patterns. The stress of being overheated for an extended period can cause your grass to wilt and weaken. The stress combined with dehydration from drought conditions can cause your grass to take on a light brown appearance, and send your lawn into a summer dormancy as the grass plants conserve energy and resources (grass dying from heat stress, fortunately, is less common). 

However, it’s important to keep in mind that a lot of the visible signs of heat stress are similar to those of some common lawn diseases. As such, if you’re noticing discoloration or poor growth on your lawn, your first course of action should be to consult your local TruGreen lawn care expert. They’ll take a close look at your grass and determine what the problem is and prescribe the proper course of action to help restore your turf’s health.

When humans get overheated, we sweat. It may feel unpleasant, but the moisture serves a purpose: It cools us down. Grass, however, can’t sweat. What it can do is pull moisture from the soil to cool itself off. Hot, dry temps, however, can dry out the soil. Without adequate moisture, grass has no way to cool itself down, ultimately leading to heat-induced drought stress.

The solution, then, seems simple: If moisture can mitigate heat stress, all you have to do is water your lawn — right? The truth is, it’s not quite as straightforward as that. It's important to supply your lawn with enough water to support healthy grass plants. But, the symptoms of heat stress can sometimes look like those of drought stress. One tip is to irrigate in the morning, when winds are generally lighter and dew is often already present. You’ll want to irrigate your lawn enough to supply 1 to 1.5 inches of water per week. Watering too much during hot weather can be just as detrimental as not watering enough. 

Mowing is also an important consideration where lawn care is concerned, but how you approach it depends on the type of grass you have. While regular mowing can help keep your lawn healthy, care should be taken if you have cool-season grass. The longer your grass is, the more water it can hold on to — and in turn, the better it’s able to keep itself cool. Our advice is to raise your mowing height during periods of hot weather, only mow when it's tall enough to be cut, and avoid mowing during the hottest portion of the day. 

For warm-season grass, you’ll want to stick to ideal cutting heights for your specific type of grass to avoid scalping or adding additional stress when temperatures subside. The ideal heights for each type are: 

• St. Augustinegrass: 2.5”-3.75” 
• Bermudagrass: 1.0”-2.0” 
• Centipedegrass: 1.5”-2.0” 
• Zoysiagrass: 1.5”-2.5” 

To keep your lawn healthy, avoid cutting more than one-third of the grass blade in a single session, as this can cause stress, yellowing, or scalping damage. If your grass is very tall, it’s best to mow in stages over several sessions to gradually reach the optimal height. 

As we’ve established, watering your lawn (especially early in the morning) can help protect your lawn during a heat wave. But it’s not 100% preventative. So, what happens if your lawn does get over-stressed from the heat? Can you get burnt grass green again?