Increased rainfall can increase mushroom and moss growth in lawns. Mushrooms are not a concern for lawns. The conditions that allow moss to grow will decrease turfgrass growth and should be amended.
During moist weather, I’m often asked if mushrooms growing in lawns are a sign of disease and if fungicides will control them. The answer to these questions is no; hence using a fungicide would be a waste of money and an unnecessary pesticide application.
While mushrooms are a fungus, fungicides will not control them, especially at this life cycle stage. Mushrooms are the fruiting bodies of fungi and most are not pathogenic, meaning they do not infect plants to cause a disease.
Along with mushrooms, the fungus is a mass of mycelium growing in or on organic matter like dead tree roots or turf thatch. They are beneficial in decomposing dead organic matter that naturally occurs in landscapes, increasing soil organic matter and some nutrients.
Cool, moist conditions promote development of the fruiting structure or mushroom. Once conditions become warmer and dryer, mushrooms will decrease. If they continue, check lawn irrigation practices to be sure you’re not overwatering.
While these mushrooms are not likely poisonous, they are not edible. Hand remove them to avoid children or pets eating them; otherwise there is no need to be concerned about lawn mushrooms.
If you wonder how fungicides work against fungal pathogens, here’s how. When fungicides are applied for plant diseases, they are applied to foliage prior to infection. When a fungal spore lands on the leaf, the fungicide then kills the germinating spore before it infects the leaf. Timing of application is critical.
Moss is a persistent weed that grows where turfgrass is thin and weak. To control moss, consider the reasons it is growing in the lawn and correct them. Moss is associated with compacted soil, poor fertility, heavy shade and excess moisture.
For effective moss control, modify conditions to favor lawn grasses. Reduce soil compaction with core aerification. Use proper fertilization and maintain a 3-inch mowing height. Too low of mowing encourages moss.
Reduce watering in shady areas where less water is needed compared to full sun areas. If feasible, prune trees and shrubs to improve air circulation and increase light penetration.
Once soil compaction and overwatering or overfertilizing in shady areas is amended, a shade tolerant grass could be sown into the area. Some Kentucky bluegrass cultivars are more shade tolerant or try a mix containing a fine-leaved fescue like red, chewings or sheeps fescue.
If a shade tolerant grass will not grow in the area, replace the turfgrass with shade plants such as Hosta, ferns or groundcovers like bugleweed.
Moss control products containing iron or copper sulfate will eliminate moss if label directions are followed, however, if poor growing conditions are not amended, turfgrass will not do well and the moss will return.
Kelly Feehan is a community environment educator for Nebraska Extension-Platte County.