An example of Fairy Ring with Mushrooms

How To Kill Fairy Rings

Fairy Rings appear as bright or dark green circles in lawns, the inside part of the circle most often is off colour, going to yellow or even dying. Fairy Rings may or may not contain mushrooms around the outer ring of the circle which is most actively growing. To examine the problem, we have to break down and look at each symptom.

Cause Of Fairy Rings

Fairy Rings can be caused by up 60 different types of mushrooms, and can occur in 3 different patterns. The first results in underground fungus only, and has no mushrooms, but the problem is exposed by the typical lush rings of growth. The next produces only the mushroom rings without any other real symptoms, and the last produces the dark green rings and mushrooms combined.

Fairy Rings - Symptoms and Death

Fairy Rings don't always contain Mushrooms

The ultra healthy outer ring is the result of the mushroom fungus feeding on the soil, and returning high levels of nutrients as a by product. The dying inner part of the circle was caused by the infection at an earlier stage of it's life. The damage occurred when the soil was fused together by a thick mat of underground threads called mycelium.

The reason for the death of the lawn in the centre is not due to an attack by the mushroom, but rather the soil can no longer absorb or retain water.

Fairy Rings Expansion

The fairy rings will usually first become obvious when the circle, or sometimes arc, is about 0.5 meter in diameter. This is the very best time to tackle this problem while it's still small, as we will discover later. Because without removal, Fairy Rings will continue to grow each year until it is destroyed or has exhausted it's food supply.

The largest fairy ring in the world is 1 kilometre in diameter, and is thought to be over 700 years old.

Fairy Rings Cure

The only cure for this problem is the removal of the turf and soil altogether, with both being completely replaced.

To remove it, the Fairy Ring must be dug out at least 30 centimetres outside of the the outer ring, and then at least 40 - 70 centimetres deep into the soil. Both soil and turf must be almost surgically removed, being very careful not to drop any of the infected turf or soil onto any other part of the lawn, otherwise a new infection will occur. The soil and turf is then replaced from new.

However, in many cases, proper care and maintenance will make the environment hostile for the fungus to continue to thrive, and it may eliminate itself, or eventually grow out.

Cultural Management Of Fairy Rings

The problem can be effectively managed in a variety of ways to slow it's progression, and to remove the damaging and unsightly effects caused to the lawn. Remember, an environment which is healthy for lawns and creates a healthy lawn, becomes a hostile environment for all pests to take hold in or to thrive in.

Aeration
Any dying areas from the inner circle can be aerated with a garden fork used to aggressively break up the soil and mycelium threads that are cementing the soil together. Coring by the use of a coring machine is an even more effective option.

Wetting Agents
An application of wetting agents over the entire lawn, and in particular the affected area should be followed next.

Fertilising
A proper year round fertilising regime should be implemented right away to increase the health of the lawn to fight the damage and the ongoing cause. Do not over fertilise.

Water
Start a proper watering regime as outlined in other articles on The Lawn Guide. Water less frequently and deeper, and do not over water.

Remove Mushrooms
Always wear gloves and carefully remove any mushrooms, without breaking them up and risking further spreading. Some mushrooms can be poisonous to both people and pets.

Sunlight
If your Fairy Rings are growing in a shaded area, pruning back surrounding foliage will allow more direct sunlight onto the lawn, allowing for a less desirable environment for the type of fungus causing the problem, and giving the lawn greater health to fight the infestation.

Vertimow
Vertimowing helps to create a healthy lawn by the removal of excess thatch. Excess thatch can also hold onto water which creates a more welcoming environment for the fungus, as well as reducing water penetration into the soil. The thatch layer can also be where the fungus actively feeds and lives during some times of the year.

Wash Lawn Mowers
Lawn mowers should be washed in a diluted bleach solution to prevent further spreading into new areas.