Diagnosing Brown Grass: Heat, Water, Pests, or Soil?

Systematic Troubleshooting for Brown Lawns

A new homeowner with Bermuda sod sees browning. Many factors can cause this—here's how to narrow it down.

1. Climate Mismatch

• Cool-season grasses (fescue, rye, bluegrass) brown/die above 85°F.
• Verify your grass matches your hardiness zone (Arbor Day zone finder).

2. Watering Practices

• Wrong: Daily 15-min cycles → shallow roots → heat stress.
• Right: Deep soak (1–3 in) once/week → deep roots → drought resilience.
• Test: Step on grass; should spring back. If not, water.
• Top-dress hot spots with compost to improve moisture retention.

3. Insect Damage

• Check for grasshoppers, leafhoppers (sap-suckers) – spray carbaryl (Sevin) if abundant.
• Dig plugs to inspect roots for grubs, billbugs.
• Treat specific pests with targeted products.

4. Fungal Diseases

• Look for leaf spots, streaks, cottony growth.
• Common: Brown Patch, Dollar Spot.
• Caused by overwatering, high humidity, excess nitrogen.
• Treat with fungicide; correct cultural practices.
• Resources: Texas A&M Plant Pathology, UNL Brown Patch, Clemson Dollar Spot.

5. Animal Damage

• Rodents (gophers, voles, moles) – traps, repellents.
• Dog urine – yellow circles; dilute with water, reseed if dead.
• Deer – fencing, repellents.

6. Subsurface Issues

• Buried concrete, rock, fill soil → localized dry spots.
• Probe with steel rod; geotech firms can map.
• Remedy: deeper soil, compost, targeted watering.

7. Chemical Damage

• Fertilizer spill, herbicide drift, salt contamination.
• Flush with water; replace soil if severe.

Action Plan

1. Identify grass type and zone suitability.
2. Switch to deep, weekly watering.
3. Inspect for insects/disease at green-brown edge.
4. Test soil pH and nutrients.
5. Treat specific problems found.

Bottom Line

Browning is a symptom, not a diagnosis. Systematic investigation—starting with watering and grass-type suitability—reveals the true cause. Most issues are correctable with cultural changes.