Fairy Rings in Lawns

Fairy rings are common throughout the world. They are more noticeable and damaging in drier locations, with lighter soils and lower fertility. The first sign of fairy rings may be a ring of mushrooms followed by rings of darker green grass with an inside border of dead grass. Small tan-coloured mushrooms usually develop on the outer border of the ring especially during rainy weather or later in the season. The cause of the ring of dark green grass is due to an increase of nitrogen in the soil, caused from the fairy ring fungus as it decomposes organic matter.

Control: There are no fungicides that will control the mycelium, or underground growth of the fungus. Heavy fertilization and watering may also help to mask the presence of the fairy ring. A complete soaking of the area, in addition to a fertilizer application can not only suppress but may even eradicate the fairy ring.

If only a few rings are present in the lawn it may be practical to excavate the affected area by removing the turf in the area of the ring along with the surrounding 18 inches of soil on both the inside and outside of the ring. The soil should be removed to a depth of at least 2 inches (5 cm) below the zone of the white fungus mat. When removing the affected areas, try to prevent any of the turf or soil from spilling onto healthy areas. Fill the area with fresh top soil and then reseed or re-sod.

Another possible method of eradication is based on the fact that when 2 rings come into contact with each other, they will exhibit antagonistic behaviour, which leads to the death of both rings. To take advantage of this natural control method, one may wish to remove the sod in heavily infested areas, cultivate the soil several times to mix the mycelium of one ring with another and then re-seed or re-sod.

Follow good turf practices of regular fertilizing and deep but non-frequent waterings

Article referenced from: http://www.gardenline.usask.ca/yards/fairy.html ,written by Bonnie Willie 
 Photo by: www.lawnsmith.co.uk