Most calls I get after a heavy rain is that “I got mushrooms all over my lawn that I didn’t have yesterday!” Yes, mushrooms can grow that fast! Mushrooms are the above ground fruiting bodies of fungi that live in the soil. These fungi feed on buried stumps, timber, tree and shrub roots, or any organic matter under the soil that has high moisture content. Most mushrooms do not damage the lawn even though they are unsightly. They are actually the “good guys” in the ecosystem of your soil since they are breaking down organic material into nutrients for your lawn. However, if there is a fairy ring (dark green or dying grass that are circular or arc-shaped) that develops in your lawn, then that becomes a different problem. Fairy rings are more difficult to control and has to be treated in other ways. For now, since fairy rings are not as common, we will just discuss mushrooms at this time.
Mushrooms are mostly unattractive & not destructive, and the easiest way temporally to get rid of them is to mow them up, step on them, or pick them and dispose of the pieces in the trash. I don’t recommend chemical controls since they are expensive with spotty results and don’t work any better then the aforementioned cultural controls. Lots of homeowners think that lime will kill mushrooms with the thought being that the soil is too acid. This does not work, since mushrooms have nothing to do with the soil’s pH.
The first and easiest way to control the rapid growth of mushrooms is to cut back on your watering. Water will speed up the decaying process, creating more mushrooms. While you can’t control the amount of rainfall mother nature gives us, just make sure you turn off your sprinkler system when you know you are going to have a lot of rain for the next couple of days; otherwise, you will have twice the amount of mushrooms. Also, too much water could lead to more destructive lawn diseases that will then need more immediate attention. The second way to control your mushrooms is to dig up the buried organic material like tree roots, pieces of wood, etc. Third, if you have enough patience, they will sometimes go away on their own, but this may take some time since this only happens once the buried organic matter is fully decomposed. I hope this clarifies some of the concerns & questions you may have about mushrooms.