Mushrooms can seem to pop up overnight, and suddenly finding a cluster scattered across an otherwise healthy lawn can be a little alarming. But mushrooms in your yard don’t automatically mean something is wrong.

“The average person that sees mushrooms growing in their lawn could easily become worried,” says Stephen Collins, founder of Supreme Lawn Worx. “In most cases, there’s nothing to be worried about.”

Instead, mushrooms in your yard can offer a few clues about what’s happening both on top of and underneath your landscaping. According to Collins, their appearance typically points to two things: plenty of moisture and organic matter. Sometimes, mushrooms can signal a lawn problem worth addressing, but other times the mushrooms in your lawn are simply part of the natural decomposition happening in healthy soil.

Here’s what mushrooms in your yard could be telling you, according to this lawn care expert.

1. Your Lawn May Have a Drainage Problem

First, let’s tackle one of the potentially problematic reasons mushrooms are appearing: Your lawn may simply be staying too wet. “You have poor drainage in your lawn and the soil can’t absorb any more water, so then it can become a breeding ground for mushrooms,” Collins says.

In other words, the mushrooms themselves aren’t necessarily the underlying problem. They’re a visible clue that excess moisture may be hanging around longer than it should. If mushrooms repeatedly appear in the same soggy areas, especially after rain or watering, it may be worth paying closer attention to how well that section of your lawn drains.

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2. Your Yard May Be Too Shady and Wet

Moisture becomes even more conducive to mushrooms when it’s combined with plenty of shade. “You have a combination of shade and oversaturated soil and have a large population of mushrooms,” Collins says. “Without the direct sunlight, this will not help the soil absorb the water.”

So if your mushrooms are concentrated beneath trees or in another particularly shady part of the lawn, the location itself may offer a clue. Wet soil that doesn’t get much direct sunlight can remain damp longer, creating favorable conditions for fungi.

3. You Could Have a Thick Layer of Thatch

Not every explanation is bad news. Mushrooms can also show up because there’s organic material in your lawn for fungi to break down.

As you mow throughout the season, Collins explains, a small layer of grass can remain on top of the soil even if you regularly bag your clippings. That layer is called thatch. “A thin layer is healthy,” Collins says, but too much thatch can contribute to mushrooms appearing.

Interestingly, the fungi are also helping with the problem. According to Collins, when mushrooms appear around excess thatch, “they are helping combat some of that thick layer.” So while excessive thatch itself may warrant attention, the mushrooms aren’t simply an invader—they’re participating in the decomposition of all that organic material.

4. Old Tree Roots Could Be Decomposing Underground

Sometimes the explanation for mushrooms in your yard isn’t visible from the surface at all. “You could just have very old tree roots that are decomposing and causing fungi growth,” Collins says.

That means mushrooms can potentially appear even where there isn’t an obvious tree stump or pile of decaying material nearby. Old roots can remain underground long after a tree is gone, gradually breaking down beneath the lawn. The fungi associated with that decomposition can eventually produce the mushrooms you see above ground.

Are Mushrooms in Your Lawn Bad?

Not necessarily—and that’s the main thing Collins wants homeowners to know. “In most cases there’s nothing to be concerned about,” he says.

Instead of immediately treating mushrooms as a lawn problem, look at the conditions surrounding them. If the area is constantly waterlogged, poor drainage or oversaturated soil may deserve your attention. If you have excessive thatch, that’s another lawn condition worth addressing.

But if your lawn otherwise seems healthy, those mushrooms may simply be a visible sign of fungi doing what fungi naturally do: helping break down organic matter that’s already in the soil.