Fungal Growth on Grass

Fungal Growth Causes

• Both environmental and improper cultural practices contribute to grass fungal growth. Lawns that have compacted soils or poor drainage conserve soil moisture that favors fungal spore germination and spread. Furthermore, a thick thatch accumulation prevents soils from drying out. Gardeners who add to the problem by excessive watering fuel the fire for fungal growth. By fixing underlining causes and removing a thick thatch layer, you can treat or prevent fungal diseases from damaging the lawn.

Removing Thatch

• Check your thatch layer by cutting a 2-inch wedge shaped piece of turf out of your lawn. Measure the brown spongy material between the grass blades and soil. Lawns that have a thatch layer thicker than 1/2-inch need dethatching. If your thatch layer is between 1 to 1 1/2 inches, dethatch twice a year. Gardeners dethatch their lawns either with rakes or power dethatchers. A power dethatcher has blades that rips the thatch through the grass blades.

Changing Cultural Practices

• Altering some of your cultural practices may treat or prevent fungal growth. Water your lawn in the morning to promote evaporation. Watering lawns late in the day or evening encouraged fungal growth. Also, some fungal diseases such as necrotic ring spot are controlled by waiting until September to fertilize, according to North Dakota State University. Fertilizing in the spring with an excessive amount of fertilizer promotes a flush of growth, which stresses out grass' root systems. Lawns undergoing stress are more likely to contact fungal diseases.

Fungicides

• Certain fungal diseases may be controlled with fungicides such as leaf spot, necrotic ring spot, rhizoctonia blight and sclerotinia dollar spot, according to North Dakota State University. When spraying a lawn with fungicides, keep up on your watering schedule. Spraying fungicides on water stressed lawns damages grass blades. Also, apply and reapply your fungicide according to the directions. Excessive rainfall and other environmental factors favoring fungal growth may determine how often to apply your fungicide.