With extended cloudy, rainy weather creating water-soaked lawns, mushrooms tend to pop up everywhere. Lawn mushrooms are the fleshy, spore producing fruiting bodies of a group of fungi which feed off decaying organic matter. This organic matter may be from rotting tree stumps or roots left in the soil, animal waste, old mulch, or decomposing grass clippings.
Since mushroom production is enhanced by damp, shady, highly organic environments, your best control is to target things you can do to help eliminate these conditions. Collecting or raking grass clippings, dethatching the lawn and replacing old mulch will help reduce the food source. Soil aerification and correcting drainage problems will improve moisture issues. Selective pruning and thinning of trees and shrubs will allow more light into shady areas.
Chemical fungicides are available that help remove existing mushrooms, but this is generally only a temporary fix as mushrooms will again appear as long as there is an abundant decaying organic food supply and favorable environmental conditions.
Most mushrooms, although unsightly, are not harmful to the turf, generally only appear during extremely wet rainy periods, and can easily be destroyed by mowing or raking. Therefore, I would not get too overly concerned about them, unless you have pets or small children that may come in contact with them as many are toxic to mammals if consumed.
Published October 31, 2011
Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. firstname.lastname@example.org