Patches on Lawn? Causes and Expert Lawn Treatment Tips

• Brown patches on lawn may be caused by brown patch, a common fungal disease.
• Brown patch spreads quickly above 80°F when humidity and moisture are high.
• Perennial Ryegrass, Tall Fescue, Bentgrass, and Kentucky Bluegrass are most susceptible.
• Overwatering, excess nitrogen and poor drainage can increase brown patches on lawn.
• Water early, mow regularly and avoid excessnitrogen to help prevent brown patch.
• Apply fungicide treatments early or at the first sign of brown patches.

Seeing patches on your lawn that look brown, dry or unhealthy? You may be dealing with Brown Patch lawn disease, a common fungus that thrives in hot, humid weather and can quickly turn healthy green grass into unsightly brown spots.

Brown Patch is most active during the summer in areas with high humidity and frequent rainfall. While it’s uncommon in arid regions like Southern California or the Mountain States, it’s a persistent problem for homeowners across much of the U.S. 

Brown Patch is caused by the Rhizoctonia solani fungus. It can infect a variety of turfgrasses, leading to irregular brown areas and dead patches on lawn surfaces. The disease spreads fast in warm, moist conditions and can cause significant lawn damage if not treated properly.

While any lawn can experience patches from Brown Patch, certain grass types are more vulnerable, including:

• Perennial Ryegrass
• Tall Fescue
• Bentgrass

Even Kentucky bluegrass can develop Brown Patch symptoms during mid-to-late summer when temperatures and humidity stay high. 

Brown Patch often begins when conditions are cool and moist, but spreads rapidly once temperatures rise above 80°F with high humidity. Nighttime dew, mist or rain can create the perfect environment for fungal growth.

Other factors that contribute to patches on the lawn include:

• Overwatering or watering late in the day.
• Poor air circulation in thick turf.
• Excess nitrogen fertilizer.
• Prolonged wet grass due to shade or poor drainage. 

While the fungus that causes Brown Patch is common, you can take steps to reduce the risk and restore your lawn’s health:

• Water early in the morning to let the grass dry before nightfall.
• Mow regularly to improve air circulation.
• Avoid over-fertilizing, especially with high-nitrogen formulas.
• Apply fungicide treatments early in the season or at the first sign of brown patches.
• Maintain balanced lawn nutrition to promote strong, disease-resistant turf.

Proper lawn care and early intervention can make all the difference when dealing with brown patches on your lawn.