Maintaining a vibrant, green lawn through the summer heat and dry conditions is challenging. High temperatures and reduced moisture can trigger protective dormancy, causing the grass to brown. Successfully resisting this involves managing environmental factors through thoughtful water application, appropriate cutting practices, and measured nutritional support.
Optimal Watering Techniques
Achieving a deep green color requires roots to extend far into the soil, seeking moisture. This is encouraged by practicing deep, infrequent watering rather than short, frequent sprinklings. Shallow watering only wets the topsoil, encouraging weak, surface-level roots that quickly dry out in the heat.
Aim to deliver approximately one to one-and-a-half inches of water per week, spread over only one to three watering sessions. This volume penetrates the soil four to six inches deep, promoting robust, drought-resistant root systems. Measure the application rate by placing a straight-sided container, like a tuna can, within the sprinkler’s reach and timing how long it takes to collect the target volume.
The timing of irrigation is equally important for maximizing absorption and minimizing disease risk. Watering should occur in the early morning hours, ideally between 4:00 AM and 10:00 AM. This allows the water to soak in before high heat causes excessive evaporation. Watering in the evening or at night leaves moisture on the grass blades, creating an environment favorable for fungal diseases.
The lawn itself will signal when it needs water, even outside a set schedule. A clear indication of dehydration is visible when grass blades fail to spring back up after being walked on, leaving persistent footprints. Another sign is a change in color from a bright green to a dull, bluish-gray tint as the plant attempts to conserve moisture. A simple test is pushing a six-inch screwdriver into the soil; if it meets significant resistance, the soil is too dry and needs hydration.
Mowing Height and Frequency
The height at which you cut your grass profoundly influences its ability to withstand summer stress. Cutting the grass too short (scalping) removes too much leaf surface responsible for photosynthesis, starving the plant and inhibiting root growth. During the hottest months, raise the mower deck significantly to allow the grass blades to grow taller.
Taller grass provides a natural, insulating canopy that shades the underlying soil and the delicate crown of the grass plant. This shading action helps to keep the roots cooler, reduces the rate of water evaporation from the soil surface, and limits the germination of weed seeds. For most common turf varieties, a summer height of three to four inches is recommended for optimal health and heat protection.
To avoid shocking the plant, never remove more than one-third of the blade length in a single mowing session, known as the “one-third rule.” For example, if the grass is four-and-a-half inches, the cutting height should not be set lower than three inches. Mowing more frequently at a higher setting is preferable to infrequent, drastic cuts.
The condition of the mower blade impacts the lawn’s color and health. A dull blade tears and shreds the grass tips instead of slicing them cleanly, creating jagged wounds. These torn tips turn white or brown shortly after mowing and make the plant more vulnerable to disease and moisture loss. Keeping the blade sharp ensures a clean cut that allows the grass to heal quickly with minimal stress.
Managing Summer Nutrition and Heat Stress
Fertilizer application in the summer requires a cautious approach, as heavy feeding can encourage a burst of growth that demands extra water and energy the plant may not have. Applying a quick-release fertilizer during peak heat can result in chemical burn, manifesting as scorched, yellow-brown patches. During prolonged heatwaves, suspend feeding entirely to avoid stressing the turf.
If fertilization is necessary, select a product with a light application of slow-release nitrogen. This formulation delivers nutrients gradually over several weeks, providing a gentle feed without forcing rapid growth or risking nitrogen burn. A simpler method is “grasscycling,” which involves leaving fine grass clippings on the lawn after mowing. These clippings decompose rapidly, returning essential nutrients like nitrogen, phosphorus, and potassium back into the soil.
Grasscycling also acts as a light layer of mulch to help retain soil moisture. If the lawn turns brown, it is often entering heat-induced dormancy—a survival mechanism where the plant sacrifices its green blades to protect its crown and roots. Determine if the grass is dormant or dead by performing a simple tug test: dormant grass resists the pull because the roots are viable, while dead grass pulls out easily. Dormant areas, especially those near heat-retaining surfaces like concrete or asphalt, can be revived with targeted watering to help the grass crown survive until cooler temperatures return.