Ask The County Agent: 'What causes a circle of mushrooms in my yard?'


By Stephanie R. Butcher, Coweta County Extension Office
QUESTION: “There is a large circle of mushrooms in my yard that seems to have appeared overnight. What causes that?”
AGENT ANSWER:  What you are describing is a disease known as fairy ring. It got its name because in medieval times people believed that mushrooms appeared where fairies had danced.
Fairy rings appear during periods of wet weather and warm temperatures like we have had over the past several months. You often see them in spring or late summer. There are many types of fungi can cause this phenomenon, but it starts out as an infected spore and then spreads outward in a circular pattern from there. They can range in size from several inches to 50 feet in diameter.
Fairy ring can look like a ring of dark green grass, circular area of bare soil where the grass has died or a ring of mushrooms like the one in the photo. The diseased area can go dormant during periods of dry weather and can become active again as soon as environmental conditions are favorable.

Fungicides are not very effective for this lawn disease, so focus on prevention or other management strategies to control it. For example, aerating your lawn during the growing season can help and keeping your lawn mowed regularly will help cover up the symptoms of the disease. Also, don’t forget soil test!
Soil nutrition is very important because the healthier your lawn is, the fewer disease problems you can expect.  Fall is the perfect time to test your soil so you can determine   whether or not you need to add lime. If you need to apply lime, fall applications are best because it takes a few months for lime to work into the soil and change the pH.  By working on improving your soils pH in the fall, your warm season lawn will benefit in the spring.
Soil tests also provide fertilizer recommendations, but make sure you utilize those recommendations in the next growing season if you test your soil in the fall. Do not apply nitrogen-based fertilizers on warm season lawns in the fall.
For more information about lawn diseases or soil testing, contact the Coweta County Extension Office at 770-254-2620 or e-mail [email protected]. Ask for the Extension publications, “Lawn Diseases in Georgia” or “Soil Testing”.
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