When snow melts and the ground begins to thaw, homeowners like you may notice patches of discolored or matted grass on your lawns. This unsightly blight is often the result of snow mold, a fungal disease that thrives in the cool, wet conditions typical of late winter and early spring. Snow mold can cause significant damage to your lawn if left unchecked, but we are here to help by giving you the knowledge you need to combat this all-too-common problem.

Keep reading to learn more about identifying and treating snow mold, and ask us how Heartland can help get rid of snow mold if you are in the Kansas City area!

What Does Snow Mold Look Like?

Snow mold is relatively easy to identify, especially as the snow melts and patches of your lawn become visible. As the snow continues to melt and the lawn begins to dry out, the characteristic fungal growth may disappear, but the damage to the grass can persist, leaving dead or weakened areas in your lawn. The appearance of snow mold can vary slightly depending on the type, but there are common characteristics to look for:

Discolored Patches: The most noticeable sign of snow mold is circular patches of discolored grass, typically ranging from a few inches to several feet in diameter. These patches can appear gray, white, pink, or even light brown.
Matted Grass: In affected areas, the grass often appears matted down and stuck together, sometimes covered with a crusty or slimy growth. This matted appearance is due to the fungal mycelium that spreads over the grass blades.
Fungal Growth: In some cases, especially in the early stages, you may see a visible layer of white, gray, or pinkish fungal growth on the grass. This growth can look like a web or a dusting of powder on the surface of the grass.
Antler-Like Sclerotia: When your lawn dries, you may notice hard, antler-like growths known as sclerotia. Sclerotia is the hardened mycelium of the fungal invasion that will continue the spread of the disease once conditions are cold and damp again.

Types Of Snow Mold

Gray Snow Mold

This variety of the disease, also known as Typhula blight, is caused by fungi in the Typhula genus (usually Typhula incarnata). The fungi within this genus only attack the grass blades of your lawn, and you can positively identify gray snow mold by waiting until your lawn dries. If the infected areas develop hardened, antler-like sclerotia as your lawn dries and warms up, you are dealing with gray snow mold. While your lawn is still wet, gray snow mold is the variety that will produce a fuzzy or cobweb-like appearance if fruiting bodies are present. This is the more common and less aggressive type of snow mold.

Pink Snow Mold

Pink snow mold, also called Fusarium patch, is caused by the fungal species called Microdochium nivale (fruiting bodies of Monographella). A pink cobweb-like growth can often be seen around the perimeter of pink mold. Pink snow mold survives as mycelium or spores in infected plant debris. Though not as common, this type of the disease causes much more damage to your lawn, as the fungus responsible attacks the roots and crowns of your grass. Pink snow mold can even develop in winter without the presence of snow cover, unlike gray snow mold.

Causes Of Snow Mold

Snow mold develops under specific environmental conditions typically associated with the winter and early spring seasons. Namely, the cooler temperatures are consistent moisture, due to both precipitation and, of course, evaporation of snow on your lawn. Identifying and understanding the main causes of snow mold is the first step in learning how to prevent and treat it when it appears on your lawn.

Prolonged Snow Cover: One of the primary causes of snow mold is prolonged snow cover. When snow falls on unfrozen ground and remains for an extended period, it creates an insulated environment where temperatures are just above freezing. This creates ideal conditions for snow mold fungi to grow and spread.
High Moisture Levels: Snow mold thrives in moist environments. High moisture levels in the soil, combined with snow cover, create a perfect breeding ground for the fungi. Poor drainage, excessive thatch, or late-season watering can all contribute to higher moisture levels, increasing the risk of snow mold.
Cool Temperatures: Snow mold fungi are most active at cool temperatures, typically between 32°F and 45°F. These temperatures are common in late winter and early spring, particularly as the snow begins to melt and the ground remains cold.
Excessive Thatch and Debris: Thatch, a layer of organic material that accumulates between the grass and the soil, can provide a hospitable environment for snow mold. Thatch traps moisture and can harbor snow mold spores, increasing the likelihood of an outbreak. Debris such as fallen leaves can also contribute to moisture retention and fungal growth.

Dangers Of Snow Mold In Your Lawn

Snow mold, while not typically fatal to grass, can cause significant damage depending on its severity and the type of mold present. In mild cases, the grass may only suffer surface-level damage, such as discoloration and matting, which can usually be remedied with proper care. However, in more severe cases, especially with pink snow mold, the fungus can penetrate deeper, attacking the crowns and roots of the grass. This deeper level of damage can lead to the permanent death of the affected areas, resulting in bare patches that require reseeding or sodding to restore the lawn. The risk of grass death increases if the mold is allowed to persist unchecked, particularly in cool, wet conditions that favor its growth.

Beyond the immediate threat of grass death, snow mold presents several other issues that can compromise the health and appearance of your lawn. When snow mold invades, it weakens the grass, making it more vulnerable to other lawn diseases, pests, and environmental stressors, such as drought or high temperatures later in the season. Weakened grass may also struggle to recover from winter dormancy, leading to a slow start in the spring and leaving the lawn looking patchy and thin.

How To Prevent & Treat Snow Mold

If snow mold is left untreated, the damage it causes can worsen over time, leading to more extensive and costly lawn care challenges. The affected areas of grass may continue to weaken, potentially leading to the spread of the fungus to previously unaffected parts of the lawn. Areas of your lawn that are weakened by snow mold damage can invite weeds to thrive and make new grass growth very difficult, which is why timely treatment is so important.

Below are some of our top tips for preventing and treating snow mold on your property, and we highly encourage you to seek professional help if you see any signs of snow mold. Preventive services like ours can help keep your lawn looking great before and after the snowy season!

Prevention

Proper Fall Lawn Care: Mow the grass to a height of 2 to 2.5 inches just before the first expected snowfall, ensuring not to leave any debris on the lawn.
Avoid Excessive Fertilization: Limit late-season nitrogen-based fertilizers to prevent overly lush growth that is susceptible to snow mold.
Manage Snow Accumulation: Avoid piling snow on the lawn, and consider removing excess snow to reduce prolonged cover.
Improve Drainage: Ensure good lawn drainage through fall aeration and proper grading to prevent waterlogging.

Treatment

Rake Affected Areas: Gently rake matted grass to promote air circulation and help the lawn dry out.
Reseed Damaged Spots: Reseed bare patches with appropriate grass seed to encourage regrowth.
Apply Fungicides (If Necessary): In severe cases, apply a fungicide in early spring to control the spread.‍
Maintain Regular Lawn Care: Continue with regular mowing, watering, and fertilizing to help the lawn recover and strengthen.

What Is Snow Mold & How To Treat It