Notice Anything Different About Your Lawn This Year?

The Northeast has experienced one of the nastiest winters it’s seen in a long time, with snow cover lasting for several straight months. As we finally see the snow disappear and begin to start in on lawn maintenance this spring, many homeowners are noticing some patches of matted and discolored lawn. This is very common in the Northeast, especially after the snow begins to melt and the ground starts to thaw; it is most likely pink snow mold or its close relative, gray snow mold.

Snow mold is a fungal disease that grows under the snow during the winter. The two types are either gray snow mold, which tends to only infect the leaf or blade of grass, or pink snow mold, which can also infect the crown of the grass and can cause more serious damage. They both manifest themselves as circular patches of dead and matted grass, anywhere from 3 – 12 inches in diameter. Pink snow mold, as its name implies, tends to have a pinkish halo around the perimeter, whereas gray snow mold tends to stay more of a white or grayish color.

Snow mold can be caused by a several different factors. The first and most obvious cause is from an extended period of snow cover on only partially frozen ground, which is a perfect breeding ground for this type of fungus. It can also be caused from leaving the grass too long in the fall, when all that grass gets matted down under the snow, it is easy for the fungus to take hold and start growing. On a similar note, it can also occur under leaves that have not been raked up in the fall; the excess moisture and matting can be a trigger for snow mold to grow.

In order to prevent snow mold from forming during the winter, it is important to perform a thorough lawn maintenance regime in the fall. Continue to mow the law until it completely stops growing, avoid excessive nitrogen fertilizer, completely pick up any fallen leaves and dethatch the lawn before the snow takes over. It is possible for snow mold to still occur, however the chances are drastically diminished.

If you notice your lawn has been affected by snow mold, it is important to treat it as soon as possible to prevent further spread of the fungus. Fortunately, it is usually fairly simple to treat and your lawn should recover nicely in a short time. Generally, a light raking of the infected areas will promote drying and encourage new growth. Heavy rakings, or dethatching as it’s called in the landscaping industry, can also be good for lawns that have suffered from severe snow mold damage; it disrupts and aerates the matted grass thus limiting disease progression and promoting recovery.

Figure 1: Pink snow mold.


(Photo courtesy of Ohio State University)

Figure 2: Gray snow mold.


(Photo courtesy of Marvin Seaman, Toadflax Nursery )

Lawn Spots was last modified: November 4th, 2016 by toadflax