What Is Snow Mold? Understanding Mold Formation Under Snow on Your Lawn

If you've noticed grey or pink patches on your lawn after the snow melts, you're not alone. This unsightly issue is likely snow mold, a fungal lawn disease that forms under melting snow.

In Ontario, especially in areas like Newmarket, Aurora, East Gwillimbury, and Uxbridge, snow mold is a common early-spring problem — and while it looks bad, the good news is it’s often treatable.

What Causes Snow Mold?

Snow mold develops when:

  • Snow covers the ground before it’s fully frozen

  • Grass is left too long in the fall

  • There’s poor drainage or heavy snow accumulation

  • Leaves and debris are left sitting on the lawn under snow

There are two main types:

  • Gray snow mold – appears in circular, grayish patches

  • Pink snow mold – more severe, can damage roots and appears in pink or tan circles

How to Tell If You Have Snow Mold

Look for:

  • Matted patches of dead-looking grass

  • A white, gray, or pink web-like fungus

  • Sections of lawn that feel slimy or spongy after thawing

It often appears in shaded or poorly drained areas.

What Should You Do About It?

✅ 1. Gently Rake the Area

Loosen matted grass to improve air flow and help the lawn dry out faster. Avoid aggressive raking if the ground is still soft.

✅ 2. Let It Breathe

Most cases of gray snow mold clear up on their own with proper sun and air exposure.

✅ 3. Overseed if Needed

If damage is severe, apply grass seed in affected areas once the soil warms.

✅ 4. Avoid Early Fertilizing

Don’t apply fertilizer too early — this can feed the fungus instead of the grass.

✅ 5. Book a Spring Clean-Up

A professional spring lawn clean-up helps prevent snow mold and promotes healthy early growth.

💡 How to Prevent Snow Mold Next Year

  • Mow your lawn short before winter (final cut around 2”)

  • Rake up leaves and organic debris before snowfall

  • Avoid over-fertilizing in the fall

  • Consider aeration and top dressing to improve drainage

📍 Serving Ontario Lawns All Spring

At Qscapes Ltd., we help homeowners across Newmarket, Aurora, East Gwillimbury, and Uxbridge recover from snow mold and other spring lawn issues. Our seasonal lawn care services include spring clean-ups, dethatching, and overseeding to help your grass bounce back strong.

📞 Get Your Lawn Back on Track

Ready to fix your lawn after a long winter? Contact us for a free spring lawn care quote.

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When Does Your Lawn Wake Up? Understanding Spring Dormancy in Ontario