Toadstools are the visible, cap-and-stem structures that appear on lawns and in gardens. They are the temporary reproductive organs of a much larger, hidden organism called the mycelium. This vast network of thread-like filaments lives beneath the soil surface year-round, feeding on decaying organic matter. Toadstools are produced only to disperse spores when conditions are favorable, usually after rain or during humid weather. Simply removing the toadstool will not eliminate the fungus underground, so effective control requires altering the fungus’s environment and removing its food source.
Identifying Toadstools and Safety Concerns
Distinguishing between harmless and highly toxic fungi is extremely difficult, even for knowledgeable individuals. A single ingestion of a poisonous toadstool can cause severe organ damage, including liver and kidney failure, with symptoms sometimes not appearing until days after consumption. Because of this toxicity risk, treat all unidentified fungi as potentially dangerous. Toadstools pose a hazard for pets and small children who might ingest them out of curiosity. If they appear in areas frequented by children or animals, immediate removal is necessary, as these fruiting bodies often emerge rapidly following warm, moist weather.
Immediate Removal and Disposal Techniques
The first step in managing an outbreak is removing the visible fruiting bodies before they release microscopic spores. Physical removal reduces the spread of spores to other parts of the lawn. You can pick the toadstools by hand, wearing gardening gloves, or mow over them if the lawnmower has a collection bag attached. Dispose of the collected toadstools properly to contain the spores by placing them directly into a sealed plastic bag and discarding them with household trash; they should not be added to a compost pile. Standard commercial fungicides are largely ineffective against the deeply buried fungal mycelium.
Eradicating the Fungal Food Source
The most effective long-term control strategy is removing the organic material that feeds the underground mycelium. Toadstools are saprophytic, feeding on decaying matter such as buried wood, tree roots, or old construction debris. To find the source, dig a small hole where the toadstools are clustered or form a “fairy ring” pattern. You will often find buried wood or roots from a removed tree beneath the soil surface. Removing the entire source, such as digging out a decaying tree stump or large root system, permanently starves the fungus.
Excessive thatch, a layer of dead and living organic matter between the soil surface and the grass blades, also provides a rich food source. If the thatch layer is thicker than half an inch, it should be removed through dethatching or scarifying. Regularly cleaning up fallen leaves and grass clippings also limits the readily available organic material that can sustain the fungus.
Changing Environmental Conditions for Prevention
Fungal growth depends on high moisture and low sunlight, so adjusting these factors makes the environment inhospitable. Improving soil drainage is a primary step, as compacted soil holds excessive water, creating the damp conditions fungi prefer. Regular lawn aeration loosens compacted soil, allowing for better water percolation and increased oxygen penetration. Evaluate watering practices, avoiding overwatering and deep watering during the evening hours. Watering deeply but infrequently, and only in the morning, allows the soil surface time to dry out before nightfall.
Increasing the amount of direct sunlight and improving air circulation further discourages fungal fruiting. Trimming or pruning dense shrubs, trees, and overhanging branches allows more sunlight to reach shaded areas of the lawn. These cultural control methods deprive the mycelium of the necessary damp and shaded environment, drastically reducing the likelihood of toadstools appearing.