Mushrooms in the yard

Mushrooms pop up instantaneously all over our yard after a good, hard rain. Some of them are just huge.

Megan Kennelly is a plant pathologist at Kansas State University. She says the biomass of fungi is in the soil, and it spends most of its lifetime underground digesting organic matter. When moisture hits and the fungi reproduce, mushrooms emerge.  Consider them beneficial.

"Some of the mushroom fungi do degrade wood. You know, like old roots or if there's any old branches or something that were kind of incorporated to the ground, you know like in new construction areas, like just weird debris ends up under the ground," says Kennelly. "And some of them do break down wood and that sense they're beneficial, because they are recycling the components of the wood."

Sometimes mushrooms form an arc or a circle. This pattern is called a fairy ring. Legend has it that mushrooms grow in circles where fairies dance. Whether you see lively winged creatures or not, fairy rings are caused by the outward growth of fungal mycelium, which decomposes organic matter. It releases nitrogen into the soil and stimulates the grass to grow darker around the outer portion of the ring.

Like their other fungal cousins, fairy rings are hard to control.

"You can just mow them off and you know, they might pop up again when the next rain comes," she says. "You're not going to be able to eradicate it because as I said most of that biomass is deep underground and you can't really get at it anyway. For a home lawn type of situation, it's better just to kind of let it run its course."

If you're well-trained in fungi favorites, perhaps you could toss them in a stir-fry.  But if you're not, don't risk it. Many mushrooms are poisonous.