One of the most common reasons mushrooms appear is the presence of organic material.
Fungi play an important role in breaking down dead leaves, grass clippings, pieces of wood, old roots, compost, and other natural materials.
When these materials are available underground, fungi have plenty of food.
The mushrooms you see are essentially the reproductive structures of fungi. Most of the organism itself may remain hidden beneath the soil.
So those white caps could be a sign that decomposition is actively taking place beneath your lawn.
2. Something May
Be Decaying Beneath the Grass
Sometimes the source is less obvious.
A buried tree root, old stump, piece of wood, or other plant material can remain underground for years while slowly decomposing.
Fungi feed on these materials and help break them down.
If mushrooms repeatedly appear in one particular area of your lawn, there could be decaying organic material underneath that spot.
This is especially common in yards where trees have been removed but their root systems remain underground.
