When temperatures cool toward the end of summer, some other growths often start popping up in the lawn alongside the grass blades and late-season weeds. Fleshy fungal projections are common in late summer to early fall, which is when assorted growths known as mushrooms, toadstools, fairy rings, and “puffballs” enter their reproductive phase. The moderate temperatures and more frequent rains moisten lawns enough to trigger colonies of these growths, leading gardeners to wonder if they ought to do something.

Mushrooms in lawn
Assorted mushrooms like these often pop up in colonies in the early-fall lawn.
George Weigel

Why are they there?

Yard fungi like these are a normal part of nature. Most help decompose fallen trees, dead logs, mulch, grass blades, and other dead wood and organic matter. You’ll often find mushroom types growing up from the decaying roots of trees that were cut down years ago (or from around dying trees).

Fungi are at work in the ground throughout the season, but people notice them mainly during their reproductive phase. That’s when they send up the familiar stems and caps of a mushroom or those odd orange appendages known as “stinkhorns.” These are the parts that produce the fungal equivalent of seeds – “spores” – that keep the organism’s life cycle going.

What to do?

Most fungal growths are harmless, amounting to a nuisance to those trying to grow a green-carpet lawn. Some are even edible, but the bad news is that a few also are poisonous. So if you’re not absolutely sure which is which – and/or have kids or pets around that might try to sample fungal growths – the safe route is to collect them, bag them, and toss them. (If a toddler or pet eats a suspicious fungus, call the Poison Control Center hotline for guidance at 800-222-1222.) Otherwise, just ignore them or kick them over to dry and decay if you don’t like the look.

Colder weather eventually will end the life cycle for the season, and the growths will fade away on their own. Unlike weeds, products aren’t readily available that prevent fungi from spreading or sprouting.