What Are Fairy Rings and Why Are They in My Grass?

Fairy rings are abnormal areas of growth in lawns that come in several forms. All have two things in common. They appear circular or arched. ⁠And that no one wants them in their yard.

What Do Fairy Rings Look Like?

Folklore says fairy rings appear where leprechauns or fairies roamed or danced, hence the name. Chris Lemcke, national technical director at Weed Man, says mushrooms make up the most common form. “The mushrooms can be in a complete circle or in more of an arc,” he explains.

A second type of fairy ring features grass that’s greener than the rest of the lawn. Also known as an accelerated growth ring, this is typically seen in large fields and golf courses.

A final type appears as dead grass, though this is less common than the others.

Their curved shape results from a fungi sending out an underground network of fine threads. These threads grow out evenly in all directions. They eventually sprout above ground in a circular pattern.

What Causes Fairy Rings?

Fungi is the common culprit behind every fairy ring. “When you see a mushroom fairy ring, it’s usually by old stumps or wood decaying in soil,” says Lemcke. The fungi (in this case, mushrooms) feed on that decaying matter. Learn how to get rid of mushrooms growing in your lawn.

Accelerated growth fairy rings result from fungi in the soil that produce a substance that speeds up the growth. Dead zone fairy rings are caused by another type of fungi that tampers with grass roots and depletes the soil of needed nitrogen.

How Do I Get Rid of Fairy Rings?

Lemcke tells homeowners not to worry about mushroom fairy rings. “They are usually short-lived, appearing in the spring, fall or whenever there are especially wet conditions,” he says. “We tell people to pick them off or mow over them.” If the mushrooms sprout near a dead stump or other decaying wood, removing the wood should solve the problem.

Properly fertilizing your lawn is your best bet for tackling accelerated growth and dead zones fairy rings. It’s best to aerate and thoroughly water a dead zone fairy ring before applying fertilizer.

“There’s no set answer on how often you should fertilize your lawn because it depends on the type of fertilizer you use,” says Lemcke, who favors slow release fertilizers with high amounts of nitrogen.