what temperature is “too hot” to mow grass. When temperatures go beyond 80°F, your cool-season grass may begin to struggle. And when high temperatures last for extended periods of time, it can cause your grass' growth to slow down and its vibrant green color to fade.
The ideal temperatures to mow are between 50 to 80 degrees Fahrenheit. Does grass stop growing at a certain height? Once temperatures have become consistently warmer, it is a good idea to follow the one-third rule, which means to never clip off more than one-third of the grass' current height in one mowing session.
Is it bad to cut grass in a heat wave? Yes, it can be. The heat leaves your grass 'stressed' and cutting it too often or too short can make this worse. If you do mow, try doing so a day or so after it rains, when your grass is likely to be happier.
Typical warm-season grass height range: 1-3 inches. During periods of peak growth, expect to mow the lawn once every 5-7 days. Conversely, during times of slowest growth, you'll mow less, if at all.
Mower Height
A mowing height between 2.5 to 3 inches is best for most of the season, except during summer stresses when the lawn mowing height should be raised one-half inch to mow at 3 to 3.5 inches. Raising the mowing height provides more insulation from summer heat and reduces water loss from your soil.
One of the most common questions we hear is, “How often should you mow your lawn in the summer?” Over the summer you'll generally mow your lawn every 4 to 6 days.
Try to water deeply and infrequently. Watering deeply means wetting the entire root zone. Watering infrequently means only watering when the grass is dry. Try to water early in the morning when your lawn can get the full benefit of hydration before the sun dries it out by mid-day.
As long as the grass is green and actively growing, lawns can continue to be mowed in summer. That's particularly true of warm-season lawns such as Bahia, Bermuda, and Zoysia grasses, which tolerate heat much better than cool-season grasses and usually keep growing throughout the summer when rain is sufficient.
Between irrigation and natural rainfall, your grass should receive between 1 and 1.5 inches of water each week during the summer. Water deeply every other day for the best results. Your turf should receive about 1/3 an inch of water every two days in order to maintain deeper roots, thus helping protect against drought.
Consequently, if the temperatures reach 95 degrees Fahrenheit or higher, you will want to avoid watering your lawn. Keep in mind, your water from the sprinkler system will evaporate off the grass so quickly, that it will not have time to seep into the root system.
As the heat starts to put stress on your lawn you may notice full brown blades of grass or grass with brown tips. They may have begun to curl.
Grass can turn brown and go dormant when it's stressed by drought, heat, or both. It's your lawn's way of conserving energy and water, Mann explains. The grass will break dormancy and begin growing again when the temperatures and/or rainfall levels become more ideal for it.
Excessively hot weather and exposure to full sun throughout the day causes a lawn to dry out and turn yellow in warmer seasons.
Heat stress occurs when the heat gets intense or long, and the grass begins to dry and die because it can't get enough water. Grass dying in summer heat can happen to all types of grasses, but some are more susceptible than others. Cool season grasses are especially prone to disease and wilting in the summer heat.
Once temperatures reach 77 degrees, it becomes too hot for root growth, and root growth ceases. When temperatures reach 90 degrees, it becomes too hot for shoot growth and the grasses stop growing and begin to fall dormant, with the surface grass turning a brown hue.
Avoid applying fertilizers when plants are dormant or under heat and drought stress. Fertilizers should be incorporated into the soil to prevent losses. If you cannot physically incorporate a fertilizer at this point in the season, it may be best to stick with a water-soluble fertilizer.
In fact, some cool-season grasses will go dormant during the hot summer months until early fall. During a heat wave—a period of abnormally hot weather that lasts longer than 2 days—it's recommended that you do not mow your lawn.
Mowing every two weeks — instead of weekly — and not dousing grass with chemical herbicides and fertilizers, helps the environment and supports the health of bees, which are among the world's most important pollinators.
It's best to wait for wet grass to dry before mowing. Wet grass clippings can clog your mower, causing it to choke and spit out clumps of wet grass that could smother and kill your lawn if left unraked. It's best to wait for wet grass to dry before mowing.
Mild fertilizer burn is when your lawn starts to yellow slightly or has brown streaks through it. When you touch mildly overfertilized grass, it'll still feel flexible and won't break when you bend a grass blade. With severe fertilizer burn, the grass will turn a shade of brown or tan.
According to Joshua Malik, owner of Joshua Tree Experts in Pennsylvania, sunburnt grass typically looks yellow or brown. Lawn areas on a hill and those that are heavily compacted are the most likely to experience scorching. That's because these areas tend to already be dry.
The good news is that the plant can stay dormant for a good while before dying so that, if the water is applied, there can be a full recovery in as little as a few days. These pictures show the damage of heat stress. If your lawn looks like this, water it!
During extremely hot weather (daytime temperatures above 90F and nighttime temperatures above 70F), try to water daily or every other day. In a 10x10-foot garden, this would mean giving your plants 8 to 9 gallons of water each day.