How to Fix Spotty Grass

Apply fungicide to diseased grass using a flat-head nozzle. Flat-head nozzles spray small droplets of fungicide, thoroughly coating grass blades. Repeat your fungicide application every five to 10 days.

Cut a 2-inch wedge-shaped piece of turf out of your yard to check the thatch layer. Thatch is the brown spongy material that builds up between the grass and the soil. Use a power dethatcher to remove a thatch layer that's over 1/2 an inch thick. Rake up the thatch debris from the yard.

Push a core aerator back and forth across the yard to improve soil compaction. A core aerator extracts 1/2- to 3/4-inch-wide and 1- to 6-inch pieces of soil. By aerating your soil, you increase the amount of air and sunlight that gets to your grass, reducing the chance of fungal diseases. Also, soil drainage improves after aerating.

Mow when your grass reaches 4 1/2 inches in height. Take off 1/3 of your grass blade, which leaves you with grass 3 inches in height. By allowing your grass to grow high, you prevent stress caused by mowing, and allow the grass to bounce back from environmental and improper cultural practice damage.

Prune back landscape plants casting too much shade. Most grass types need six to eight hours of sunlight. By allowing more sunlight, your grass receives more sun for photosynthesis, and fungal spores dry out. Fungal spores thrive in moist, shady environments.