Snow Mold: What It Is and How It Forms on Lawns

Snow mold is a type of fungal disease that can affect lawns during the winter months. It is caused by two different types of fungi: grey snow mold (Typhula spp.) and pink snow mold (Microdochium nivale). These fungi grow and thrive in cool, moist conditions and are often found under snow cover. So let’s dive deeper into everything about Snow Mold: What it is and how it forms on lawns:

The fungi that cause this issue are present in most lawns, but they only become a problem when the conditions are right for them to grow and spread. The ideal temperature for growth is between 0°C to 10°C, which is why it is commonly found in areas with prolonged snow cover.

When there is snow cover on the lawn, the snow creates a moist, humid environment that is perfect for the fungus to grow. The longer the snow stays on the lawn, the greater the risk of developing. This is because the snow cover can create an insulated layer that traps heat and moisture, which encourages the growth of the fungi.

Snow mold can also develop in areas where there is no snow cover but the conditions are still cool and moist. This can happen in areas where there is a lot of shade or where the lawn is not getting enough sunlight to dry out.


The symptoms of snow mold can vary depending on the type of fungus that is causing the problem. The grey version typically appears as circular or irregular patches of greyish-white turf, while pink snow mold appears as circular or irregular patches of pink or greyish-white turf. In both cases, the affected grass may appear matted down and may have a web-like substance covering the blades. In severe cases, the grass may turn brown and die off completely.


The best way to prevent snow mold from forming on your lawn is to make sure it is in good health before the winter months. This means fertilizing the lawn in the fall and keeping it mowed to a height of 2-3 inches. It’s also important to remove any fallen leaves or other debris from the lawn before the snow falls. This can help prevent the buildup of moisture and heat that can encourage the right conditions. Aeration in the fall can help improve air circulation and prevent the buildup of moisture that can lead to snow mold.


If you do notice snow mold on your lawn, the first step is to rake up any matted down grass to allow air and sunlight to reach the affected area. You can also lightly rake the affected area to help break up the web-like substance on the blades of grass. In most cases, the grass will recover on its own once the snow melts and the conditions become less favourable. However, if the damage is severe, you may need to reseed or sod the affected area. In some cases, it may be necessary to apply a fungicide to prevent further growth. However, this should only be done under the guidance of a lawn care professional.


Snow mold is a common problem for lawns in areas with prolonged snow cover. It is caused by fungi that thrive in cool, moist conditions and can lead to circular or irregular patches of matted down grass. To prevent it from appearing it’s important to keep your lawn healthy and free of debris before the snow falls. If you do notice snow mold on your lawn, you can take steps to help the grass recover on its own or seek professional help if necessary.

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