Thatch

• A thatch buildup of more than 1/2 inch can contribute to a decrease in air circulation, which promotes fungal disease growth. In fact, gardeners can avoid dealing with fungal-diseased turf if they remove their thick thatch, according to North Dakota State University. You can tell how thick your thatch layer is by cutting out a 2-inch wedge from your turf. Measure the brown, spongy material that sits between your grass and soil. Use a dethatcher and remove the thick layer of thatch if it is more than 1/2 inch. Reseed bare areas exposed by the dethatching.
  
  

Fertilizing

• Spreading too much nitrogen over your lawn can cause burnt grass, because nitrogen contains salts that can dehydrate your grass blades. Prevent grass burn by spreading the correct amount, applying fertilizer at the right time and watering after your fertilizer application. Furthermore, gardeners should fertilize their lawns in the fall with 1 lb. of nitrogen per 1,000 square feet, according to Cornell University. Spring fertilizing promotes a flush of top growth of your grass without benefiting the roots. This flush of growth is susceptible to fungal disease and pest problems.
  
  

Watering

• Overwatering can encourage fungal disease. Saturated grass and nighttime temperatures create a hospitable environment for fungal diseases. Grass needs 1 inch of water a week, according to Cornell University. If you grass receives 3/4 inch of water for the week, supplement the rest of the water. Avoid watering in the late afternoon to prevent fungal diseases. By watering in the morning, you allow the grass blades to dry out before cool nighttime temperatures.
  
  

Mowing

• Sharpen your mower's blades every year at the beginning of the growing season. Dull blades wound grass and provide entryways for harmful pathogens. Avoid taking off more than 1/3 of the grass blade at a time. Mowing too close to the ground weakens your grass' root systems. Generally, gardeners can keep their grass at 3 inches for healthy growth, according to Cornell University. Refrain from cutting any shorter unless you are growing a grass variety such as zoysia, which can handle a short mowing height.