Snow Mold Prevention and Spring Recovery for Northern Lawns

Every spring I get calls about mysterious dead patches that appear the moment the snow melts. Across most of the cool-season belt, pink snow mold (Microdochium nivale) is the common one. Gray snow mold needs long-lasting snow cover, so it shows up mostly in the snowiest areas, and it can be more damaging.

Prevention Starts in Fall

• Do not apply heavy nitrogen fertilizer after mid-October. Late nitrogen keeps grass growing when it should be hardening off.
• Keep mowing until growth stops. Long, matted grass under snow is a perfect environment for snow mold.
• Improve drainage and reduce thatch. Snow mold loves compacted, thatchy turf that stays wet.
• Remove leaves and debris in late fall so they don’t trap moisture against the turf.

Spring Recovery

When the snow melts and you see the classic tan or pinkish patches:

1. Rake vigorously to break up the matted crust and improve air flow. This is the single most important step.
2. Lightly fertilize with a balanced or high-nitrogen starter fertilizer to encourage new growth.
3. Reseed thin areas as soon as soil temps allow (usually mid-April to May, later the farther north you are).
4. Raise mowing height slightly until the lawn fills in.

Related: Dog Spots or Lawn Fungus? How to Tell the Difference · Fall Grub Damage: Skunks, Raccoons, and What to Do Now

Photo: Snow mold and snow on turf by Maasaak, BY-SA 4.0.