How to Prevent Snow Mold on Your Lawn Before Winter

What Is Snow Mold?

Snow mold is a fungal disease that appears under snow cover during winter. Two types affect lawns: gray snow mold (Typhula blight) damages grass blades, while pink snow mold (Microdochium patch) kills crowns and roots.

Signs of Snow Mold

In early spring, look for circular patches of matted, discolored grass — gray mold shows straw-colored patches; pink mold displays pinkish fungal threads at patch edges.

Prevention Strategies

1. Final Mow Before Winter

Cut your lawn shorter for the last mow of the season — about 1.5-2 inches. Long grass mats down under snow, creating ideal conditions for fungal growth.

2. Remove Fallen Leaves

Clear all leaves before the first snow. Trapped leaves hold moisture against grass blades and create perfect fungal habitats.

3. Avoid Late-Season Nitrogen

Stop applying high-nitrogen fertilizer 6 weeks before expected first snow. Late nitrogen promotes tender growth susceptible to disease. Switch to potassium-rich fall fertilizer instead.

4. Improve Drainage

Aerate compacted areas in fall. Better drainage means less standing water under snow cover.

Treating Snow Mold in Spring

• Rake affected patches gently to dry out matted grass
• Apply fungicide if pink snow mold is present (it kills crowns)
• Overseed bare spots once soil reaches 50°F
• Most gray snow mold lawns recover naturally as grass resumes growth