A brown lawn is a frustrating sight for any homeowner, signaling a problem that needs immediate attention to restore a healthy, green appearance. While discoloration is the most visible symptom, it is not a specific diagnosis, as several underlying factors can cause grass to turn brown. Successfully reviving your turf requires correctly identifying the root cause, whether it is environmental stress, insect damage, or a fungal disease. Understanding the specific nature of the problem is the first step toward applying the correct treatment.
Identifying the Root Cause of Brown Patches
Determining the reason for browning involves a close inspection of the damaged areas and the grass itself. Drought stress or dormancy often results in uniform browning across a large area, but the grass blades remain firmly anchored when pulled. This occurs because the plant is conserving energy, and the roots remain intact. If the grass resists a gentle tug, the issue is likely environmental stress.
Pest damage, particularly from white grubs, presents differently, usually appearing as irregular, isolated patches of dead grass. White grubs are the c-shaped larvae of beetles that feed on grass roots, severing the connection to the soil. If you can easily lift or roll back the turf in a damaged area, much like peeling back carpet, grub activity is the probable cause. Digging a small, one-square-foot section can confirm the presence of more than five to ten grubs, which is the threshold for significant damage.
Fungal diseases like Brown Patch and Dollar Spot create distinctive patterns. Brown Patch typically manifests as circular or irregular patches ranging from a few inches to several feet in diameter. In early morning dew, an active Brown Patch may display a dark, grayish border known as a “smoke ring.” Dollar Spot creates smaller, straw-colored spots, often about the size of a silver dollar. Individual grass blades within these spots may show lesions with tan centers and reddish-brown borders.
Rehydrating Stress-Induced Turf
If the cause of browning is water-related stress, implementing a deep, infrequent watering regimen promotes recovery. The goal is to encourage deep root growth, making the grass more resilient to future dry conditions. Shallow, daily watering encourages roots to stay near the surface, making them vulnerable to heat and rapid drying.
A single watering session should deliver approximately one to one and a half inches of water per week, allowing moisture to penetrate four to six inches into the soil. Check this depth by pushing a long object, such as a screwdriver, into the soil after irrigation. This deep soaking ensures the entire root zone is saturated, and the soil should dry out slightly between waterings.
Timing is important for water management, especially for minimizing disease risk. Watering in the early morning, typically between 6 a.m. and 10 a.m., is the optimal window. This timing allows the grass blades to absorb moisture before midday heat causes excessive evaporation. The morning sun also dries the grass blades completely, preventing the prolonged leaf wetness that promotes fungal pathogens.
Remediation for Pests and Fungal Disease
Remediating biological issues requires targeted treatments based on the initial diagnosis. White grub control relies on either preventative or curative insecticides.
Insecticide Timing
Preventive treatments, such as those containing chlorantraniliprole or imidacloprid, are applied in late spring or early summer to target grubs as they hatch. Curative insecticides, often containing carbaryl or trichlorfon, are applied later in the season, typically in late summer or early fall, when grubs are actively feeding near the soil surface. Curative applications are necessary when damage is visible, but they are generally less effective than preventive measures. Both types of products must be watered into the soil immediately after application to reach the root zone.
Managing Fungal Diseases
Fungal diseases are managed with a combination of chemical and cultural practices. If a fungus is confirmed, a broad-spectrum or targeted fungicide application can halt the spread, though it will not immediately green up the dead grass. Cultural practices modify the environment to make it less hospitable for the fungus. This includes improving air circulation by pruning surrounding shrubs and avoiding watering that leaves the grass wet overnight.
Establishing Long-Term Turf Health
Establishing long-term turf health prevents future browning episodes. A soil test provides a detailed analysis of the soil’s pH level and nutrient composition, eliminating guesswork in fertilization. Grasses thrive in a slightly acidic to neutral pH range, typically between 6.0 and 7.0. An imbalanced pH can prevent the grass from accessing available nutrients.
Soil Structure Improvement
Aeration and dethatching are mechanical processes that improve soil structure, which is beneficial for compacted ground. Core aeration removes small plugs of soil, relieving compaction and allowing water, air, and nutrients to penetrate deeper into the root zone. This process, often paired with overseeding, encourages new growth and fills in thin areas damaged by stress.
Mowing and Fertilization
Proper mowing height is a simple cultural practice that builds resilience. Cutting the grass too short stresses the plant and exposes the roots to excessive heat. Maintaining the recommended height for your grass type shields the soil, conserves moisture, and encourages deeper root development. When the grass is recovering, fertilization should be light, using a slow-release formula to provide steady nourishment without forcing rapid, vulnerable top growth.