Identifying & Treating Snow Mould in Your Spring Lawn

Submitted on February 22, 2019

While spring weather may still feel far away, warmer temperatures will slowly begin to return over the next month or so. While signs of spring are very exciting, this is also the time of year when winter turf damage begins to reveal itself. What many homeowners don’t realize is that extended periods of damp, cold weather can create the perfect conditions for turfgrass disease. As the snow begins to melt, homeowners should keep their eye out for signs of snow mould.

What is Snow Mould and How is it Identified?

Snow mould is a common turfgrass disease that often develops in northern turf grass species during the early spring after the snow melts. It causes patches of discolouration in the grass, often emphasized by strands of webby, fungal material known as mycelium on the lawn.

Homeowners usually notice areas of discolouration on their lawn signifying the presence of either gray or pink snow mould. Gray snow mould typically appears in patches that are light brown, gray, or straw-coloured that are usually less than 10 inches in diameter. These patches can merge together to form one large pattern. Pink snow mould often appears in patches that are yellow, tan or salmon-coloured, with the outer edges appearing pink. These patches are typically 1-8 inches in diameter, but they can also form into larger patterns.

What Causes Snow Mould?

Gray snow mould requires snow coverage for the disease to be prevalent. This usually means snow coverage that was present for at least 90 days. Pink snow mould, on the other hand, is prevalent during temperatures of around 16 degrees Celsius and in areas prone to more alkaline soil.

Also, your lawn is more susceptible to the development of snow mould if it has poor drainage, matted down grass, dense leaf coverage and excess thatch present over the winter months. For this reason, following appropriate cultural practices in the fall is key to preventing snow mould the following spring.

Preventing Snow Mould

Snow mould will typically disappear with the improvement of environmental conditions. However, following these cultural practices will ensure that your turf remains healthy and free of potentially harmful disease:

  • Cut your grass until it stops growing in the fall

  • Don’t leave your grass too long over the winter, as it can get matted down causing disease

  • Remove all debris from the lawn (this includes raking leaves before the winter!)

  • Manage thatch build-up by aerating or raking your lawn in the fall

  • Improve drainage on your lawn

  • Apply only moderate levels of nitrogen fertilizer in the fall

  • Avoid putting down late applications of fertilizer in the fall, as it stimulates growth before dormancy

Treating Snow Mould

While preventing snow mould is your lawn’s best defence against harmful disease, it is also important to know what to do if your lawn becomes affected. If you notice snow mould on your lawn, you should gently rake the area to loosen any grass that has been matted down over the winter. This will allow your lawn to breathe and help your turf recover faster. If you notice that these areas are not recovering over time, you may need to consider reseeding the areas when growing conditions are ideal.

If you ever have questions regarding the condition of your spring lawn, do not hesitate to contact your local Weed Man! We would be more than happy to help.

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