I'm very curious about this. There's a new/old house in my neighbourhood, i.e. an old house converted into some very stylish, smaller homes (four of them). But the nicely cared-for lawn along the side of the property is just covered with mushrooms. Does anybody know why this would be? Note: This is in Vancouver, BC.
I have heard of this happening before when there is a lot of woody, organic matter in the soil or perhaps applied as a dressing over an existing lawn.
Often comes up as what is called Fairy Rings over here on lawns. I found that aeariation is the best cure, but once it gets hold it is difficult to remove. Individual picking before they mature is also best. As Margot stated, the mycelium was more than likely present in the topsoil used to lay the lawn.
