How to Handle Snow Mold

In the winter months, most lawns require less maintenance and care. And when the snow covers your yard, it's easy to assume that your lawn is dormant and doesn't need care until spring. However, mold can form beneath the snow, harming your grass without any signs or indications.
To keep your lawn in its best shape, know what causes mold to grow in winter months. By getting ahead and educating yourself upfront, your spring lawn will thank you. Here are the two types of snow mold and how to fight them, starting in the fall.



Snow mold

As snow melts, you may notice there are matted, crusty regions of your lawn, which is a sign of snow mold. Snow mold occurs when a deep, early snow cover prevents the ground from freezing, which then triggers fungal growth between the snow and unfrozen ground. There are two types of this mold: gray (Typhyla blight) and pink (Fusarium patch).
Gray snow mold is white to gray in color. Hard structures (sclerotia) may develop on leaves and crowns of affected plants. The formation of sclerotia can help you to distinguish the difference between gray and pink snow mold. Gray snow mold stops growing when temperatures exceed 45 degrees or when the ground dries.
Pink snow mold appears from white to pink in color. Occasionally, fungal fruiting bodies (mushrooms) may develop. This can happen with other molds too, so look at the coloration of the mold. Pink snow mold may continue in wet weather if the temperature is between 32-60 degrees.


How to avoid

Snow mold is not an annual occurrence for most lawns. It most often occurs when a deep layer of snow falls before the ground freezes, and is more common in northeastern states. To help prevent the growth of mold, continue to mow until grass is completely inactive in the fall. The final height of your yard's grass should be about two inches. Follow a fertilizer program to make sure that your lawn contains adequate levels of phosphorus (P) and potassium (K) to prevent mold formation. Avoid an excessive use of fast-release nitrogen fertilizer, as it may cause mold to form.
Also avoid thatch, poor drainage and large amounts of leaves from collecting in your yard. These materials and environments could cause poor aeration and trap moisture, which helps mold spores grow. To prevent this from occurring, you can simply rake your lawn at the end of the fall to improve air circulation when snow falls.


How to fix snow mold

In most cases, it will gradually disappear as temperatures increase. Snow mold does not survive in warm temperatures and will die off as the weather becomes warmer. Infected areas may have weak or dead turf that will take longer to green than the rest of the lawn. Overseeding may correct severe damage since grass seed is placed directly into the turf without tearing the soil. To overseed your lawn, you need to remove any debris, such as leaves; mow remaining grass to about 1 ¼ inches, and aerate the soil. Aerate the soil before seeding to improve your lawn's drainage and allow oxygen to reach plants' roots. This process should help to eliminate mold and repair damaged spots of turf.