The Treatments for Fairy Ring Fungus in Grass

Fairy Ring Fungus

• Fairy ring fungus refers to any of 60 types of fungus that infest lawns and fields. They grow in rings, which grow larger every year. The grass inside the ring is stimulated by the nitrogen the fungus produces as a by-product and becomes darker green and lusher than the rest of the lawn, creating disfiguring circles. Different types of fairy ring fungi produce different fruiting bodies, like toadstools and puffball mushrooms. They can be poisonous and should be removed if small children or pets might eat them.

Mild Infections

• Fairy ring fungus thrives in lawns with a thick layer of thatch left on top of the grass from mowing and trimming. The thatch protects the spores and gives them a place to grow and feed. For mild infections, treatment begins with removing the thatch from your lawn and not allowing it to build up again. If this does not help, aerate the infected portion of your lawn, rototilling the grass back down into the soil. Soak the aerated area with the hose and keep it wet for at least 24 hours. This disrupts the fungus, which does not like water. It will prevent the fairy ring from coming back.

Severe Infections

• For a more severe infection, soak the area with water for a longer period of time, about three or four days. Aerate the soil and soak it for a few more days. If this does not work, remove the infected portion of your lawn, taking sod a foot down into the soil and in a foot wide barrier around the fairy ring and replace it with new sod. Fungicides are ineffective against this type of fungus.

Considerations

• Do not soak soil that contains tree roots, as the constant presence of water could lead to root rot. You can try to disguise fairy rings in your yard by using more nitrogen fertilizer on the healthy areas of grass. This causes the entire lawn to come in darker green and lusher, but it will not do anything to solve the fairy ring fungus issue. Keeping thatch raked up and watering your lawn well can prevent fairy ring fungus from infecting it in the first place.