Brown patch, dollar spot, and other fungal infections are among the most common causes of brown patches in lawns. These diseases thrive in warm, humid conditions and spread rapidly if left untreated, creating circular or irregular brown areas.

Waterlogged soil and poor drainage create ideal conditions for fungal growth and root rot. Excess moisture prevents grass roots from accessing oxygen, causing them to weaken and die, resulting in brown, dead patches throughout your lawn.

Grubs, chinch bugs, and other lawn insects feed on grass roots and blades, causing brown patches to appear. These pests are particularly active in late summer and fall, and their damage can quickly spread if not addressed with proper treatment.

Fertilizer burns, herbicide damage, gasoline spills, and pet urine can all cause brown patches on your lawn. These chemical injuries kill grass blades and roots, creating distinct brown areas that may take time to recover or require reseeding.

Heavily compacted soil restricts root growth and water penetration, weakening grass and making it susceptible to disease. Areas with high foot traffic or poor soil structure are particularly prone to developing brown patches that resist recovery.

Improper mowing height, infrequent watering, and lack of fertilization weaken grass and make it vulnerable to disease and stress. Neglecting regular maintenance reduces your lawn's ability to fight off brown patch fungi and other damaging conditions.