Tales from the Help Desk, Uninvited Mushrooms

Q. Why are mushrooms in my yard? How can I get rid of them?

A. Mushrooms tend to pop up in the fall due to shady, cool, and moist conditions and the availability of organic material in the lawn. The mushroom is the fruit of an underground feeding network (mycelium) of fungal threads (hyphae). Fungi feed on decomposing plant material and make that material accessible to the grass growing in the yard. Mushrooms do not damage the lawn and can be considered a sign that the soil is healthy below the surface. Mushrooms are a here today, gone tomorrow issue.

They typically have a short lifespan, ranging from a few days to a week to possibly a month. However, the underground mycelium persists – to the benefit of the soil and the various plants living in that soil. If you find it difficult to consider mushrooms an interesting yard ornament or are concerned that children or dogs may digest the mushrooms, there are options.

First, do NOT spray with a fungicide; typically, this will not kill the mushroom because the fungicide will not reach the underground mycelium. A more appropriate approach is to break the mushrooms off at the base and place them in a bag. Close the bag and dispose of it in the trash. Do not put mushrooms in a compost pile; do not mow over mushrooms. Both these options will scatter the mushroom spores and encourage more mushrooms in the future. You can make a mixture of 5 tablespoons of vinegar per gallon of water and spray the vinegar mixture on the area where you just eliminated the mushroom to reduce the probability of a recurrence. However, when the vinegar mixture comes in contact with the grass, it can damage/kill the grass – potentially leaving you with circles of dead grass where formerly there were mushrooms. You can reduce the probability of mushrooms by pruning trees and shrubs to reduce shady areas, avoiding overwatering, aerate the lawn to improve drainage, and dethatch the lawn to reduce the amount of available organic matter.