Lawn Disease Identification Part 2: Snow Mold

If you aren’t familiar with snow mold, count yourself lucky! However, if you’ve noticed circular or irregular shaped whitish-gray/whitish-pink patches on your lawn, they may in fact be snow mold.

Let’s look at a the chief causes and how you can conquer this disease through prevention and maintenance, including aeration. If you need help, don’t be afraid to call in some extra help from Valley Green Companies.

Gray Snow Mold, Typhula Blight (Typhula Spp.)

Gray snow mold survives the summertime in the thatch layer of your lawn, and begins to grow in the winter. This mold generally only attacks the leaves of grass.

It grows best underneath snow on unfrozen ground. It can grow at temperatures slightly below freezing and can continue after the snow melts, as long as the grass remains cool and wet. Once the temperature hits about 45° F or the surface of the grass dries, it stops growing.

Gray snow mold appears as brown, matted down spots on the lawn, ranging in diameter from an inch or two to more than a foot. Fuzzy whitish-gray strings may stretch across and out from the area. Occasionally you may see mushrooms appear from the infected portions of your lawn.

Snow Mold by noricum

Snow Mold

Pink Snow Mold, Fusarium Patch (Michrodochium Nivale)

Pink snow mold survives the summertime in the thatch layer of your lawn, and begins to grow in the winter. This mold generally attacks the leaves of grass, but can also kill the crowns and roots of your grass. Pink snow mold is generally more serious than gray snow mold.

It grows best underneath snow on unfrozen ground. It can grow at temperatures slightly below freezing and can continue after the snow melts, as long as the grass remains cool and wet. Pink snow mold can continue growing in the spring or resume growing in the fall as long as the temperature is between freezing and 60° F.

Pink snow mold appears as brown, matted down spots on the lawn, ranging in diameter from an inch or two to more than a foot. Fuzzy whitish-pink strings may stretch across and out from the area. Occasionally you may see mushrooms appear from the infected portions of your lawn.

Prevention And Mitigation

Once you’ve identified that you have pink or gray snow mold, there are some steps you can to fight the mold and prevent it in the future.

  • First, you want to avoid adding excessive levels of nitrogen to your soil. Nitrogen-rich soil is very conducive to mold growth, so having a proper lawn care and fertilizer plan is important.
  • Another important piece is to make sure to spread out snow over the winter to encourage quick melting in the spring. Use snow fencing if needed to prevent drifting in problem spots.
  • Gentle raking of the affected area is also beneficial, as it can help dry out the grass and slow or stop the growth of the mold.
  • Be careful with your mowing. Mowing more than ⅓ of the blade off at one time, mowing too infrequently or mowing your grass shorter than 3-3-½” can add unnecessary stress to your lawn.
  • Lastly, you’ll want to reduce the amount of thatch you maintain on your lawn. Anything more than ½” is too much and can be reduced by the process of lawn aeration. Lawn aeration removes soil cores from your lawn and deposits them above the thatch layer. This helps breakdown the thatch. At Valley Green Companies, we utilize special aerator equipment which creates 40 holes per square foot.

Remember, if you need help we’re right down the road. Give us a call today!