Mushrooms are resilient, and it can be difficult to get rid of them when they show up in your lawn. Mushrooms, also called toadstools, refer to a common type of fungi that help decompose dead matter, such as dead plants. The ecosystem needs mushrooms and other types of fungi, and most types of mushrooms won't damage your grass. However, they can spoil the look of your lawn and provide a safety hazard for children. Mushrooms grow best in wet conditions, so you're most likely to notice mushroom growth after it rains.
You can rake up or mow over mushrooms, but this doesn't kill the root system of a mushroom. The visible parts of mushrooms are the fungi's fruit, which releases spores. However, raking or mowing over mushrooms may prevent their regrowth until the next deep rain.
Dethatching your lawn may reduce mushroom growth, because some mushrooms survive by decomposing the organic matter in thatch. In addition, if your lawn is excessively wet from over-irrigation or drainage problems, fixing the source of excess moisture may reduce mushroom growth.
Applying fertilizer can also help reduce mushroom growth, because fertilizer increases the rate at which organic matter decomposes. Apply 1 pound of readily available nitrogen (not slow-release) per 1,000 feet of grass.
Most mushrooms are harmless to grass, but fairy ring mushrooms may damage your lawn. Fairy ring mushrooms are mushrooms that grow in rings or circles. This type of fungi can overwhelm the soil, causing grass to yellow or die. Apply nitrogen fertilizer to fairy ring mushrooms and aerate the grass to break up the fungus in the soil. Fungicides are not usually effective on fairy ring mushrooms.
Many varieties of mushrooms are toxic, so never eat mushrooms found in your lawn or in the wild unless you have been trained to identify species of mushrooms. Don't let young children or pets play on your lawn until you have removed all mushrooms and teach children not to touch or eat wild mushrooms.