Grey Snow Mold


Grey snow mold grass disease


North (only)

Cool Season Grass

Grass species affected

Disease occurrence

  •  Late-fall through early-spring
  • Grey snow mold requires prolonged: snow cover; cool, wet conditions; or deep snow cover on non-frozen ground.


  • Circular straw, light-yellow to grey patches when the snow first melts that will enlarge as the lawn reminds cold and wet.
  • Grass has a matted appearance.
  • In ideal conditions, you’ll notice a thin, fluffy covering of fungi that looks like stretched-out cotton covering the patch.
  • Generally, infected areas are a little slower to green up.


  • Avoid excess application of nitrogen in the fall. A slow-release, low-nitrogen fertilizer, such as Milorganite, should be used for dormant fertilization.
  • Rake up leaves in fall.
  • Distribute large piles of snow to encourage rapid melting.
  • Gently rake the affected areas to promote drying.
  • Regularly dethatch your lawn.

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