Recently, my daughter gave me a scare when she walked up to me in the yard, a mushroom in hand with a clean bite taken out of it, and asked, "Can you eat this?" A rushed phone call to poison control followed, which was followed by a long 24 hours of watching for any poisoning symptoms. Luckily, the mushroom was either non-poisonous or Elsa did not swallow the bite she took. Of course, the incident was followed by quite a bit of research on lawn mushrooms.
As a general rule of thumb, mushrooms are not harmful to the lawn. Surprisingly, most lawn mushrooms are beneficial. The hyphae, or underground portion of the fungus, feeds off decaying organic matter, such as tree roots, leaves, or pieces of wood. Nitrogen is released during the fungi's feeding process, which in turn feeds the lawn. This is why your lawn may look dark green in areas where you observed mushrooms a short while ago.
Most of the mushrooms found in our lawns are stinkhorns, puff balls, birds nests, lawn mower's mushroom, and ink caps. Fortunately, the majority of mushrooms found in the lawn are not poisonous. Some can cause gastric upset, and a few are toxic. Because some are toxic, parents of young children and pet owners worry about mushrooms in their lawn.
Mushrooms are hard to remove from the lawn. There are no known chemicals that can be used to get rid of lawn fungi. Mowing over the mushrooms only temporarily removes the fruiting structure, which will reappear when the weather conditions are right. The only true way to remove a lawn fungus is to remove the organic material the fungus is feeding on. This process involves digging down into the soil to find the material and completely removing it.
For most people, this task is too time consuming and difficult. A simple solution is to hand pick and dispose of mushrooms as you see them. This will not remove the mushrooms permanently, but will temporarily solve the problem without spreading the spores (the fungi's equivalent of seeds). The more important step, which we are working on at our house, is to teach young children to never pick or eat mushrooms. As we have learned, this step takes frequent reminders - never, ever eat a mushroom from outside!
Anne Lenox Barlow has had experience in the agricultural field as a horticulture educator with Cornell Cooperative Extension in Clinton County. She can be reached by e-mail at firstname.lastname@example.org.