Seeing mushrooms pop up in a lawn can cause a land manager to panic, especially after working hard to maintain a healthy turf. However, it’s important to know that these fungi are a natural part of a healthy ecosystem and, in most cases, don’t require drastic action. Understanding why mushrooms appear can help you choose the right approach.

Fungi: The Good vs. The Bad

It’s crucial to understand that the fungi that produce mushrooms are not the same fungi that cause turf diseases like brown patch or rust. Mushroom-forming fungi are saprophytes, meaning they decompose dead organic matter like buried wood, old tree roots, or thatch. They act as nature’s recyclers, releasing valuable nutrients into the soil that benefit the grass. They are not parasitic and will not harm the turf itself. In contrast, fungi that cause turf diseases are pathogenic, meaning they attack and feed on living grass plants, leading to brown, dead patches or rust-colored spores. The appearance of mushrooms is a sign of a healthy, biodiverse soil environment, not a sign of disease.

Why Mushrooms Appear

Mushrooms are the fruiting bodies of a fungus’s underground network, the mycelium. This vast network of thread-like filaments breaks down organic material. The mushrooms are simply the reproductive structures that emerge to release spores, much like an apple is the fruit of an apple tree. The appearance of mushrooms is often a response to favorable conditions, such as prolonged periods of rain or high humidity.

Management and Misconceptions

For most lawns, the best course of action is to do nothing. The mushrooms will typically disappear on their own as the weather dries out. For turf used for sports or recreation, you might remove them to prevent tripping hazards. However, it’s important to remember that removing or crushing mushrooms does not kill the fungus. It only removes the visible part and temporarily reduces the spore load.

A common misconception is that chemical treatments will solve the problem. Spraying household chemicals like bleach on a mushroom’s location is ineffective at killing the deep-seated mycelium and can harm your grass and the environment. The best way to reduce mushroom populations is to manage the conditions that favor their growth. This includes improving soil drainage, reducing excessive irrigation, and removing buried organic debris.

The Magic and Science of Fairy Rings

Our ancestors found a supernatural thrill in fairy rings. They believed these perfect circles were places where fairies danced, and crossing into one could be dangerous. Today, we know that these rings are caused by a fungus growing outward from a central point. The mycelium expands in a circular pattern, producing mushrooms on the newest growth. The ring of mushrooms is often accompanied by a ring of lush, dark green grass because the fungus releases nitrogen as it breaks down organic matter. NC State Turffiles reports that more than 70 species of fungi have been associated with fairy ring formations.

According to NC State Extension, there are three types of fairy rings:

• Type I: The fungus makes the soil water-repellent, killing the turf in a ring. This is most common in hot, dry weather.
• Type II: A ring of lush, dark green grass appears due to the release of nitrogen.
• Type III: A simple ring of mushrooms or puffballs, most common after heavy rainfall.

While they are generally harmless, cultural practices can help manage them. These include seasonally-appropriate core aerification to break up the mycelium, deep watering to re-wet hydrophobic areas, and applying nitrogen fertilizer to mask the symptoms of a Type II ring. Removing buried woody debris before planting turf can prevent fairy rings from starting. Fungicides are generally ineffective once you see symptoms, as they only work as a preventative measure.

Sit Back and Enjoy Your Lawn’s Part in the Ecosystem

Mushrooms in turf are a natural and often beneficial part of a healthy ecosystem. For most land managers, the best approach is to let nature take its course. Understanding that the mushrooms are a symptom, not the problem, and that their removal or chemical treatment is largely ineffective will save time, effort, and money.

Note: Wild mushrooms should never be eaten unless verified by an “approved mushroom identification expert”. Do not harvest wild mushrooms if you have never been trained to identify mushrooms, as many mushrooms can look similar and misidentification can be fatal. Mushrooms are not generally poisonous through skin contact, but can be highly poisonous when ingested. N.C. Cooperative Extension does not provide edible mushroom identification services.

Amanda Bratcher is the Horticulture Agent for North Carolina Cooperative Extension in Lee County.