Summer heat-stress presents a serious problem for regional lawns, especially in July and August. Hot temperatures, dry weather, and foot traffic tax on most types of grass, allowing weeds and bugs to move in. Changing a few simple habits—like cutting your grass to a certain length and watering it during the right time of day—helps your lawn to withstand environmental stressors. Additionally, planting the right type of grasses in the first place, or using a supplemental seed on bare patches, lends resilience to your backyard haven.
Grass and Heat Stress
Extended periods of summer heat, bright sunshine, and warm nights with no rain equal trouble for a well-manicured lawn. In northern climate zones, cool-season grasses, especially, become stressed, wilted, and prone to disease. The heat and lack of rain may dictate a ramp up on watering efforts, but excessive moisture can allow diseases, like fungus and rot, to set in. Thankfully, grasses have a built-in adaptation to summer conditions. They utilize the energy stored in their root system to sustain themselves, while also shrinking their roots during drought to reduce water consumption and loss. Some varieties may even go into dormancy during summer. Recognizing these traits is the first step in assisting your lawn through the heat by playing Mother Nature yourself.
If you're starting a lawn from scratch, you're one step ahead of combating the brown yard game (and the effects of global warming, too). Select drought-resistant seeds like fescues, buffalograss, and wheatgrass that are fast growing, establish themselves quickly, and require little maintenance. These grasses have been used for years to set lawns in Western and Midwestern arid environments, but with the changing climate, they may be suitable for other zones too. Check your local nursery for drought-resistant varieties that require little watering and are also good for your zone. Then use the seed to either start your yard or fill in bare patches.
Spring prep pays off later in the season. This is when your grass creates the extensive root system needed to help it withstand the seasonal stress. While counterintuitive, new practices deter homeowners from fertilizing their lawn. Strong chemicals—which sometimes add unneeded synthetic nutrients—can be harmful to children, pets, and groundwater. Instead, skip fertilizing in the spring and opt for a mulching mower instead. A mulching mower allows mulched grass to settle into the lawn. This helps reseed bare patches (essential in spring), while also trapping the moisture needed to keep the lawn cooler and better hydrated. Cut early to help the grass proliferate, then use your mulching mower throughout the summer to maintain homeostasis.
In the same way long hair keeps your neck from getting a sunburn, longer grass also keeps the sun's harmful exposure at bay. Keeping your grass at a longer length during the heat of summer also allows the roots to extend deeper into the earth and fuels the plant to out-compete weeds for precious resources. Additionally, bigger roots equal a denser turf, requiring less water in general. Set your blade height to about 4 inches mid-summer.
Mowing less frequently and earlier in the day, or as the sun goes down, helps with summer drought conditions too. Freshly cut grass is more likely to sustain damage in the hot sun, so mowing when it's cool will cut down on brown spots.
Maintaining your mower by keeping its blade sharp allows for a clean cut, void of fraying. Frayed blade conditions happen when the grass splits vertically and tears along the top surface. Frayed grass requires much more water than that of a clean cut. So to avoid a brown haze on the tip of your grass, make sure your mower blade is in top working condition.
In summer, most lawns require about an inch of water per week to stay healthy. This is easy to achieve early on when spring rains are present. But come midseason, nature's irrigation turns off, requiring supplemental hydration from you. Do so mindfully, paying particular attention to the time of day you water. If you water in the heat of the day, most moisture will be lost to evaporation (and it's wasteful, to boot). But early morning or late evening watering allows moisture to be efficiently absorbed by the root system. If there's a water restriction in your community, abide by the rules and only water on the days you're supposed to. And if a total water ban is present, you may be out of luck altogether. However, even a well-established brown lawn should come back after watering is resumed.