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.
Signs of Lawn Stress
On the bright side, heat stress is not that difficult to identify. Early on, your lawn may need a drink if footprints remain on the grass hours after walking on it or if the grass appears discolored (it usually turns gray or a darker shade of green before going brown).
Set your mower blades high
Set your mower blades on the highest level for your grass. Taller grass grows deeper roots and deeper roots access more water and nutrients for a stronger, more resilient lawn that can bounce back from heat stress.
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 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.
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.
When your lawn has heat damaged, it doesn't just turn brown — the dead, brown grass will eventually disappear and reveal the ground beneath it. These bare patches of ground are easily susceptible to weeds. This is why you need to cover bare patches of your lawn with seeds in order to try and regrow the grass.
Water deeply and infrequently (2-3 times per week). Morning watering is highly recommended, as afternoon watering can lead to early evaporation, while night watering can cause various forms of turf disease. Refrain from mowing too low.
However, if your lawn is heat-stressed, avoid fertilizer products. Lawn fertilizer on a heat-stressed lawn can have the opposite effect and can cause further damage to an already sensitive grass area.
If there are especially dry or hot conditions, try watering your lawn to revive brown grass. Don't worry. If your grass is dormant, it will naturally green up again in the spring.
Mowing high gives the lawn a deeper and larger root system, keeps moisture in, defends against weeds and keeps the soil cooler. Mowing too short during dry conditions can injure or wear out dormant grasses to the point where they may not come back during cooler conditions.
You'll often see grass looking a little bluish-purple/gray instead of bright green when it's starting to get stressed. Usually this goes hand in hand with the footprints in the lawn symptom. A golden yellow or brown lawn.
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.
A dormant lawn is not a dead lawn. With the right care, your lawn can survive a drought and come back lush and green as soon as the water comes back.
It is ideal to water lawns about one inch of water per week. To determine how long you need to water to get one inch, place a plastic container in your yard and set a timer. On average, it will take 30 minutes to get a half inch of water. So, 20 minutes, three times per week will give a lawn about an inch of water.
Watering in the morning also helps your lawn stay cooler throughout the hottest parts of the day, decreasing the amount of heat stress for the turf. If you are unable to water in the mornings, early evening (between 6:00 PM and 8:00 PM) is the next best time.
With a lack of water and high sun exposure, lawns can become scorched. Sunburnt grass typically looks yellow or brown. It's possible these areas can even die.
Follow Watering Schedule
That can make it difficult to know if the grass is still alive. You can get a better idea of what's causing the brown color by following a consistent watering schedule. Watering will help dormant grass become green again, while dead grass will remain brown.
Bad news: If the grass is totally dead due to drought, there's no way to bring it back. However, reviving brown lawns that are simply dormant usually occurs within three to four weeks of regular irrigation.
Avoid watering grass on a hot afternoon when it's 95 degrees or higher. The best time to water grass is at dawn or in the early evening. Water deeply three times a week instead of a little water daily. Test whether your sprinkler system is watering your lawn evenly.
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.