My lawn has a circle that’s darker green than the rest of my lawn. What’s going on? Two words: Fairy Ring.
So, what is a fairy ring and what causes them?
On a recent walk in our neighborhood, I came across a lawn showing symptoms of fairy ring.
It was my wife that asked me why. So, I thought I would share.
Fairy rings are circular areas of abnormal growth that are found in turf.
The darker green color can be attributed to decaying organic matter below the surface of the turf.
The name dates back to the middle ages where it was thought that fairies were dancing on the turf.
There are 3 different types of fairy rings attributed to different fungi. Type I can cause death in turf, Type II causing areas to grow darker green. This seems to be the type of fairy ring seen in this picture:
Type III can support mushroom growth in a circular fashion. More information can be found at this link from Wisconsin:
https://hort.extension.wisc.edu/articles/fairy-rings/
All 3 feed on decaying organic material.
The question is always “Do they hurt anything?” The short answer is No.
But some homeowners find it annoying or unsightly.
Core aeration can help cut down on thatch.
In addition, nitrogen fertilizer can help green up the turf surrounding the fairy ring and making the whole turf color more uniform.
Fungicides may be effective in a highly managed grass stand like a golf course. But many of these are not labeled for home turf use. A list of chemistries can be found in the following article from North Carolina State:
https://www.turffiles.ncsu.edu/diseases-in-turf/fairy-ring-in-turf/
In an article from University of Maryland, overall turf health with adequate fertilization and irrigation can help.
https://extension.umd.edu/resource/fairy-rings-lawns/
As the article points out, excessive fertilizer in lawns can end up leaching from turf and may add those nutrients to bodies of water prone to Harmful Algal Blooms.
https://bygl.osu.edu/node/1291
Soil testing allows to target nutrient application as pointed out in this OSU Fact Sheet:
https://ohioline.osu.edu/factsheet/hyg-5812
If you are patient, when the turf uniformly starts to green up when active growing occurs, the fairy rings may be less obvious.