Mushrooms In The Lawn? Could Be A Fairy Ring

We have received several questions this summer about mushrooms growing in your lawns. Have you noticed any this year? It seems to have been a good year for them here in central NJ and PA.

One of the most common ways that mushrooms appear are in fairy rings, mushrooms that pop up in a circle or arc.

Fairy rings are so common in some parts of the world, such as England and Scotland, that there are folk tales, legends, paintings and literature about them. Even Shakespeare mentions them in some of his works. The name itself, “fairy rings,” alludes to the legend that the rings in meadows and forests were caused by fairies (or, occasionally, elves) dancing in a circle in the moonlight.

But what causes these strange rings, and what can you do if you spot mushrooms in your own lawn?

Where Do Fairy Rings Come From?

Like apples on an apple tree, mushrooms are the “fruits” of an organism called a mycelium. The mycelium grows underground, feasting on whatever nutrients are available, most often from decaying organic matter such as old tree roots, stumps, or lumber. As it grows, it expands outward, leaving the center behind.

If it decides to produce mushrooms, they then appear above-ground in a circle pattern (or sometimes an arc). Occasionally, the grass will appear darker in a circle as well, even if no mushrooms are produced.

Any type of mushroom can appear in this circular pattern, and, if left undisturbed, will generally produce an ever-widening circle of mushrooms each year.

Fairy rings appear often during rainy, warm periods. You may notice them anytime from the beginning of spring until late into fall. They often develop on lawns that are under-watered, sandy, or poorly fertilized.

Are Fairy Rings Harmful?

While interesting enough to inspire folk tales and a fun name, fairy rings can pose certain threats. The fungi underground can prevent water from reaching your lawn.

In addition, many types of mushrooms are poisonous, which can be dangerous if children and pets run around your lawn.

How Do You Recognize Fairy Rings?

fairy ring dark circle

Fairy rings often appear as circles of darker grass in the lawn.

Appearing first as darker patches of lawn (caused by the nitrogen released by the underground fungus), fairy rings can appear in the middle of the lawn or near trees. They can range in diameter from only a few feet to as many as 20 feet. If they run into a sidewalk or a flower bed the circle will not grow there.

How Can I Remove or Prevent Fairy Rings?

You have several options in dealing with fairy ring mushrooms. You may collect them (but do not eat them!) and compost them, mow them when you mow your lawn, or knock them down with a rake or hoe.

Note that this will only be collecting the “fruit” of the organism, and so the mushrooms will most likely appear each year (the mushrooms are its way to trying to ensure its survival).

To prevent this, we have several methods that we can use. Fairy rings and associated mushrooms are common in nutrient-poor soil so the first step is to perform a soil test to determine the nutrient profile of your soil.

We then correct any nutrition deficiencies with organic fertilizer and amendments to build a healthy soil profile.

If darker green patches of grass appear in a circle, core aeration for improved water penetration may be helpful.

Consistently maintaining your lawn to keep it healthy is the best prevention for fairy rings.

Contact us today for a complimentary consultation to create a lawn treatment program that will keep your lawn in top-notch shape – and free of fairy rings.

Bill Grundmann

Bill is the owner of Organic Plant Care, LLC. He takes an integrated approach to tree care, focusing not only on the trees themselves but also on the surrounding environment, managing tree health from the "ground up" - healthy soil equals healthy plants. Bill is a New Jersey Licensed Tree Expert and NJ Approved Forester with over 35 years of experience in the tree care industry.