By: Staci Miller, Paulding SWCD, Education Specialist
Are your lawns forming magical rings in the grass? Due to the recent heavy rainfalls and warm temperatures many home owners are discovering fairy rings. They are dark green circles, arcs, or rings of thick, fast-growing grass that develop anytime from green-up in the spring through the heat of summer until the first hard frost in the fall. These rings are most commonly between two and 15 feet in diameter, although they may be larger or smaller. Mushrooms or puffballs may appear under wet conditions in the same ring pattern. In some cases, a ring of brown or dead grass may appear.
Fairy rings are caused by many different soil inhabiting fungi of the class Basidiomycetes. Fairy ring fungi do not attack grass directly, but break down organic matter in the soil. As a result, nitrogen is released which the grass uses, causing it to grow and develop a contrasting green ring. The mushrooms that appear after rainfall are the fruiting bodies of the fungus. Fairy rings break down organic material such as old tree stumps, roots, logs, lumber, and other larger pieces of organic material in the soil below the lawn. Once this material is depleted, the fairy ring will disappear, but it may take a significant amount of time. Several fairy rings may appear relatively close together, especially on lawns that exist on sites that were previously wooded areas. When this occurs, it becomes noticeable that fairy rings do not cross each other, as fungal activity ceases when fungi from different rings contact each other.
There are approximately 50 species of fungi are known to form fairy rings in turf, with Marasmius oreades, Agaricus campestris, Lycoperdon spp, and Scleroderma spp being the most common. These fungi decompose organic debris in the soil and thatch. A fairy ring starts from a piece of mycelium or spore at a single point feeding in the thatch layer or organic soil matter. The uniform outward growth of the fungus results in the development of rings. Under certain conditions, and with certain fairy ring fungi, a ring of dead grass develops. Some of the responsible fungi have been shown to penetrate and kill root cells resulting in dead rings of grass. There are some ways cover up the fairy rings or remove the fairy rings if they become a nuisance to your lawn.
The use of a nitrogen fertilizer can mask the symptoms of fairy ring by causing the rest of the lawn to green up. You can remove the fairy ring and get to the root of the problem by identifying and removing the organic debris that caused the ring to form then establish a new lawn by planting clean, ring-free sod for your new lawn space. Another option is to eliminate thatch buildup with a dethatching program. There are fungicides available for suppression of fairy rings, however, results may be only temporary as the decaying material may still be present. Sources of information for this article were provided by Missouri Botanical Garden. The fairy rings are truly a natural process that can add some character to your lawn and can be a conservation piece for you and your neighbors.
For more information, contact Staci at Staci.miller@pauldingswcd.org
