Just outside the dark ring the grass sometimes turns brown and becomes thin. The soil is compacted as the fungi moves through it, making it difficult for water to penetrate the soil. The life cycle of fairy ring fungus is typical of most fungi, Goodspeed adds. It survives in the thatch and soil throughout the winter. The dormant fungi becomes active in the cool, wet spring and continues to grow outward throughout the summer and into the fall.
Mushrooms appear in the area after heavy rains or when the turf is heavily watered.
Fairy ring mushrooms feed on decaying organic matter, he says. They often appear where a tree has been removed, or if there is some decaying wood or an old, thick thatch layer in the turf. These dark green rings vary in size from one to ten feet. They may look like a full circle, a semi-circle or as just fragments of a circle. The real trick to controlling fairy ring is simply keeping it out of the yard in the first place, Goodspeed says.