Mushroom in the Lawn:
by Rob Sproule
During wet summers people come into the greenhouse everyday asking what they can use to get rid of the mushrooms sprouting in their lawn. The good news is that they won’t harm your grass and will disappear as moisture levels fall. The bad news is that, other than snipping off the toadstools, there’s nothing you can do.
What are they?
Think of the visible portion of a mushroom as a flower. Below it there’s a vast network of microscopic filaments, called hyphae. When hyphae binds together to form a mass of white or dark threadlike growth, it’s called a mycelium. This is what you would find beneath that humble toadstool.
Just like a plant waits for the right conditions to flower, the mycelium waits for sufficient moisture to “bloom” (send up mushrooms). In dry years, the fungus simply waits under the soil for enough rain to fall.
Fungus look small, but when filaments keep threading together they can form massive organisms. A mushroom in eastern Oregonis often described as the largest living thing on earth and covers 2,200 acres.
Like bacteria in your body, there’s fungus throughout every healthy yard even though you only see a fraction of it. Fungus lives off rotting organic matter and, in the process, converts much of it to nutrients for other plants to utilize. So while it’s not the sexiest group of plants around, it’s actually one of the most useful.
The white mushrooms in your lawn are feeding off old thatch, buried bits of wood, and other assorted decaying matter that the mycelium is wrapping around. If you have an older lawn, annual aerating to clear out the thatch would be good start to reducing their numbers.
Surface mushrooms are fruiting and their only goal in life is to spread spores. Try to pick them before they can do this, as each of the countless spores they release into the air will become hyphae of their own and will seek to build new underground infrastructure.
When you mow your lawn, you may want to use a bag if they are widespread. Collecting the shredded fungus bits in a bag will keep them, and the developing spores, off the lawn.
If you’re willing to do anything to keep the mushrooms off your prize lawn, I bet you won’t be after reading this. There’s no chemical treatment, and the only way to make sure they’re gone is to dig them out. You’ll need to dig up the entire yard down deep enough that you can’t find any more white strands of mycelium. This is often several feet deep.
As if the thought of that isn’t distasteful enough, after that there will probably still be hyphae that you don’t see, which will promptly resume work growing, weaving, and getting thicker, until one wet summer day you’ll look out the window and get an unpleasant surprise.
My advice is to learn to live with them, and if you’re so inclined take the opportunity to learn about fungus and the amazing role it plays in our ecosystem.
Can I Eat Them?
When people ask me if they can eat the mushrooms in their lawn, I tell them if they have to ask, they aren’t sure enough to eat them. While we have many edible (and downright delicious) edible species in Alberta, we also have toxic species that can and have killed on multiple occasions.
If you want to learn about eating mushrooms, talk to someone who can take you out and show you what is edible and what isn’t. Don’t go by pictures on the internet or from a book alone, no matter how innocent they look sitting in the yard.