Animal Urine

Animal urine, particularly female dog urine, can kill grass due to its high salt concentration. Urine causes grass to turn yellow, with green rings that form from the nitrogen content in the urine. Train your pet to go elsewhere to avoid such mishaps. Alternatively, you can use artificial or removable turf to protect the grass.

Rinse the affected area as soon as you notice it to avoid grass damage. Scratch up the dead material, treat the area with a neutralizer like gypsum, and flush the spot with water to limit the urine’s effect. You can also reseed the spot and keep the area moist during seedling establishment.

Lawnmower

Lawnmowers can cause brown spots on grass if you do not properly maintain them. Dull blades can tear the grass, which will damage it and lead to the death of the grass. Sharpen the blades on the lawnmower before the fall and spring when you might mow grass frequently. Additionally, examine the grass after mowing to ensure the mower cuts it cleanly.

Chemical Contamination

Chemical contamination can cause brown spots on grass if fuels, fertilizers, herbicides, or pesticides spill onto the lawn. If you apply fertilizer unevenly or incorrectly, it can burn the grass. Insect repellents can also burn lawns when sprayed directly onto the grass blades.

Do not overfill your lawnmower’s fuel or oil tank, and refill the tank away from the lawn. This way, you can spill fuel on the driveway if you make a mistake, not on the lawn. Also, follow the application directions for the fertilizer and repellents.

You can wash away insecticides, herbicides, and fertilizers to reduce their effect on the grass. However, an oil spill will require you to dig up the contaminated area.

Drought and Poor Soil Quality

Drought can cause dry, compacted spots, which will impact grass health. Thus, the grass will start to die, and the resulting brown spots may be patches of dead grass if a lawn does not receive adequate water. Hand-water or use in-ground irrigation or lawn sprinklers to prevent dry grass.

Poor soil quality can cause bare or mossy patches. Test the soil quality before you plant and add fertilizer, organic matter, or other soil additives. Additionally, buried debris can cause brown spots, so check for hidden items.

Insects

You can identify insects as the cause of brown spots by the uniform shape of the affected areas and the presence of birds that feed on the pests. Grubs, billbugs, and chinch bugs are among the most common culprits.

You can easily identify grubs if you pull back a section of sod to inspect for fat, white curved worms. You can identify chinch bugs by their black and white adults. Other pests, such as caterpillars, leave behind eaten-looking grass blades as evidence.

Apply insecticides, or introduce beneficial nematodes or milky spore disease with the help of experts to control insects. Proper lawn maintenance can also deter insects since they prefer damp conditions.

Diseases

Brown spots on grass can develop from various fungal diseases, including brown necrotic ring spots, patch fungus, Pythium blight, pink snow mold, summer patch, gray snow mold, red thread, rust disease, and dollar spots.

Lawn owners may need to increase air circulation and sunlight, take a sample of the affected area to a local cooperative extension office for analysis, use lawn fungicides, and alter how they fertilize, water, and maintain their lawns to treat these diseases.