After several days of rain, you may walk outside and suddenly find mushrooms scattered throughout your lawn. It is common for homeowners to worry that this means their lawn is unhealthy, diseased, or in need of a fungicide treatment. In most cases, there is no reason to panic. Mushrooms are common during wet weather and are generally harmless to your grass. In fact, they are often evidence of the natural activity happening beneath the soil. Why Are Mushrooms Growing in My Lawn? Mushrooms are the visible part of fungi living beneath the soil. They commonly appear when there is plenty of moisture and organic material for the fungi to break down. In our experience, we see the most mushrooms following excessive rainfall. They also frequently appear where old tree roots, buried wood, or tree stumps are slowly decomposing underground. This is why mushrooms may continue returning to the same lawn year after year. Even after a tree is gone, its root system can remain beneath the soil for ...