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Snow Mold! It’s Not About Putting Snow in a Mold

As the snow begins to melt, you may start to see a grayish, and sometimes pinkish, circular straw-like, matted patch in your yard, especially near the street where snow was piled up for what may have seemed like decades to some but was only a few months. The spot can also have a “webby” fungus appearance. If you have this phenomenon in your yard, then click on this link to learn about snow mold and what you can do to prevent it from happening again next Spring.

Janelle Rietz-Kamenar, Master Gardener

Snow Mold!   It’s Not About Putting Snow in a Mold

Snow Mold is a fungus that develops and thrives when early, deep snow covers the ground prior to the ground being frozen.  Snow mold can continue to grow once the snow has melted in the Spring as long as the conditions remain wet and cold.  

There are 2 types of snow mold found in Minnesota:

  1. Gray snow mold produces sclerotia which look like dark, hard round bodies on the grass blade.

  2. Pink snow mold produces pink-colored spores and fuzzy mycelium.



Areas of your lawn that are affected with snow mold will generally take longer to green up in the Spring but usually come back to normal and therefore, is not usually too serious.  In a bad weather year, it can, however, kill the grass.

If you want to “spring” into Action this Spring:

  • You can choose to break up and spread the larger snow piles around in the affected areas.  This will help the snow melt faster and dry out quicker.  

  • You can gently rake the area to create a faster drying process and prevent further mold growth.

Preparation to avoid snow mold altogether must be done in the Fall with these easy steps:

  • If your yard is prone to snow mold, skip a Fall nitrogen fertilizer which the fungus thrives on.

  • Continue to mow your lawn until the grass stops growing.  Cut grass to 2 inches (but not shorter) to prevent the grass from matting and allowing mold to grow.

  • Rake up leaves

  • If you have certain areas in your yard where snow mold is a problem, consider a snow fence to reduce large piles of snow.

While snow mold can be a little unsightly in the Spring, a few actions can help alleviate the problem quickly!  


Source:

University of Minnesota Extension: “Snow Mold Prevention Begins in Autumn”, October 20, 2023


Photo Credit: University of MN Extension (1,2)

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