Mushrooms in the Lawn and Fire

Yesterday, it finally happened!! I viewed little round mushrooms on one of my new lawns for the first time this year. Their activity had been sparked by at least 5 inches of rain over the past 10 days and they had broken out in force. The strange thing is that they were not there over the weekend when the lawn had been mown..... scary stuff.

I am often asked about the reasons why mushrooms appear in lawns when they have never done so in the past. It seems that mushrooms on your lawn(s) puts the fear of God into lawn owners.

As with any lawn 'disease' you need a Pathogen, Host and Environment in a triangle of equal sides to see the Pathogen (the mushrooms) appear.

The Host is of course the grass plants but more importantly the soil underneath and the Environment is the prevailing climatic conditions. Although the presence of mushrooms in your beloved sward does not mean that the lawn is diseased, the Disease Triangle as it is known follows the same principles as the Fire Triangle, which has Oxygen, Heat and Fuel forming the side of the triangle to make it all happen.

The soil is in fact full of millions of micro organisims and bacteria and soil fauna, all doing their bit in keeping the soil healthy and most fungi and bacteria are the friendly sort of chaps that you could take back to meet your Mother for Sunday tea. A bit like the 'friendly bacteria' that we are encouraged to drink each morning to keep our stomachs healthy.

The pathogen often white in colour strands (Mycelium) that causes mushrooms to come up on your lawns are always present in the soil and some are linked to the sites where old tree stumps or old trees had been once. When conditions are just right and the sides of the triangle resemble the more traditional equilateral triangle shape of all sides equal in length as learnt at school, hey pesto like the white rabbit coming out of the Magicians' hat, the fruiting bodies of the fungi suddenly appear on the surface.

The mushrooms will not harm the grass. They often appear in newly laid turf too. Simply collect the fruiting bodies ahead of mowing and discard them. If you are a bit gung ho and mow over them, expect more next year. They will appear of their free will each year when the environment is just right, mostly warm and moist.

If you notice darker rings of grass and the presence of mushrooms, you may have what are know as Fairy Rings and this Technical Leaflet on Fairy Rings is here to help you should this be the case.