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Gray snow mold and pink snow mold

What is Snow Mold?

Winter is here, and even though your lawn is going dormant, stay watchful. Snow molds might take over, turning your healthy lawn into an infested tundra.

Snow molds are fungi that affect turfgrasses during winter. The most common types are pink snow mold and gray snow mold.

Description of Snow Mold

The fungi attack grass under layers of snow and leaves. Cool, humid environments under blankets of snow and wet leaves are perfect conditions for the molds to grow. Almost all types of grasses—such as fescues, Kentucky bluegrass (a common grass in Utah), and ryegrasses—are susceptible to snow molds.

Identifying Snow Mold

Snow Mold

Cool, matted grass underneath piles of snow provides perfect conditions for snow mold fungi to develop.

Pink snow mold first appears as 2-inch, brownish-orange circles. The condition can grow to be 12 inches wide and can range in color from light gray to tan. Usually, the dead patch has a ring of light pink webbing, called mycelium, on the outer edge. Pink snow mold can also grow under wet debris (not just under piles of snow).

When gray snow mold first appears, it causes the grass to appear light yellow, like the color of straw. As the snow mold continues to grow, mycelium may appear on the turf. The grass may start to take on a grayish hue and develop fuzzy mold-like growths on the surface. Gray snow mold needs colder temperatures to grow, so it generally only develops beneath piles of snow that sit for long periods of time.

Treatments for Snow Mold

Snow molds are easier to prevent than to cure. A few tips for preventing snow molds are as follows:

  • Remove leaves and grass mulch to help winterize your lawn.
  • In the fall, the last time you mow your lawn for the year, cut the grass 2 inches tall to prevent the grass from getting matted down. This can help prevent snow molds from forming.
  • Avoid piling heaps of snow onto grass, especially in shady areas where the snow melts slowly. Piles of snow take much longer to melt, giving snow molds time to grow.

Snow often hides the fungi, so sometimes homeowners don’t know they have snow molds until the snow melts. Lawns with little damage will recover on their own. To get rid of snow mold on your lawn, try the following:

  • Remove snow from shaded areas.
  • Spread out piled up snow.
  • Rake up areas with substantial damage to break up snow molds.

Preventative actions are important because gray snow mold will go dormant during the summer and drop into the thatch area. If not treated, snow mold will appear next winter.

Watching for snow molds and taking necessary actions will prevent the disease from overtaking your yard. If you have trouble identifying snow molds, Stewart’s can help. Call us at 801-226-2261.

 

Photo Credit: RICCI’s Landscape Management Inc.

Sources:

https://extension.usu.edu/archive/beware-of-the-abominable-snow-mold

https://extension.usu.edu/millard/ou-files/snowmold.pdf

 

Watch our video for more information about snow mold.