Why Is Fungus Growing in Your Yard?

June brings longer days, lush greenery, and the unmistakable scent of summer. But for many homeowners, it also brings something less welcome: mysterious patches of mushrooms or fuzzy mold popping up in the yard. If you’ve noticed fungal growth in your lawn or garden this month, you’re not alone, and you’re not powerless, either.

 

Warm, Wet Weather: The Perfect Storm for Fungus

Fungi thrive in environments that are warm and moist. June often delivers just that, especially if your region has experienced heavy rains or high humidity. Wet soil, coupled with warm nighttime temperatures, creates the ideal breeding ground for fungi.

Common weather-related conditions that encourage fungus:

  • Overwatered lawns or poor drainage

  • Long stretches of rain followed by heat

  • High humidity and dew-covered mornings

Common Yard Fungi in St. Louis

Here are the most commonly reported fungi in the St. Louis metro area:

1. Brown Patch

  • Affects tall fescue and ryegrass

  • Shows up as large, circular brown areas with a dark outer ring

  • Most active during warm nights (above 68°F)

2. Pythium Blight

  • Grows rapidly in hot, humid weather

  • Appears greasy or water-soaked

  • Often mistaken for heat stress or drought damage

3. Dollar Spot

  • Causes small, silver-dollar-sized tan patches

  • Prefers low nitrogen soil and moist conditions

4. Fairy Rings

  • Dark green rings with mushrooms or bare centers

  • Caused by decomposing organic matter like old tree roots

5. Slime Mold and Mushrooms

  • Typically harmless to grass

  • Often appear after several rainy days

Is It Harmful?

Most lawn fungi are not dangerous, but they can be unsightly or indicate a deeper lawn health issue. For example:

  • Mushrooms are usually not a threat to your grass but can be a hazard to pets or children if toxic.

  • Fungal lawn diseases like dollar spot or brown patch can damage turf if left untreated.

  • Mold and mildew can weaken plants and attract pests.

Prevention and Control

If you want to reduce fungal growth, take a few proactive steps:

  1. Improve Drainage: Aerate your lawn and avoid overwatering. Water early in the day to allow grass to dry before nightfall.

  2. Clean Up Organic Debris: Remove dead leaves, clippings, and other decaying materials.

  3. Mow Smart: Keep your mower blades sharp and don’t cut the grass too short.

  4. Fungicides: For persistent or harmful fungi, you may consider using an appropriate fungicide. Always follow label instructions or consult a lawn care professional.

  5. We carry top products like: BIOADVANCED Fungus Control | 3336F® Fungicide | HERITAGE G Granular And more!

Bonus Tip: Fungus Can Be a Sign of a Healthy Ecosystem

While it may seem counterintuitive, the presence of mushrooms and fungi often indicates your soil is rich in organic material. So, unless it’s damaging your turf or plants, a bit of fungus isn’t necessarily bad news, it might just mean your yard is alive and well.