As the winter snow melts, homeowners often eagerly anticipate the return of a green lawn. However, that receding snow can sometimes reveal a nasty surprise: crusty, straw-colored patches covered in what appear to be spiderwebs.
What Is Snow Mould
If you are wondering what is snow mould, it is a fungal disease that thrives under snow cover when air circulation is poor. While unsightly, it is rarely fatal to residential lawns and can be managed with a few simple steps.
How To Get Rid of Snow Mould?
The good news is that for most residential lawns in the GTA, snow mould is a cosmetic issue that resolves itself as temperatures rise and the soil dries out. If you are wondering how to get rid of snow mould, you can speed up the recovery process by following these steps:
- Wait for the Lawn to Dry: Before doing anything, ensure the ground is firm enough to walk on. Walking on a squishy, waterlogged lawn can cause soil compaction, which is far more damaging than the mould itself.
- Rake the Affected Areas: Once the lawn is dry, gently rake the matted patches. This is the single most effective way to treat snow mould. Raking breaks up the crusty layer of mycelium (the fungal threads), allowing air to circulate and drying out the fungus.
- Apply Fertilizer: A light application of nitrogen fertilizer in the spring helps the grass outgrow the disease. By encouraging new blade growth, you can help the lawn recover its green color quickly.
Note: Fungicides are rarely necessary for home lawns. They are typically reserved for golf courses or extreme cases of pink snow mould where turf death is likely.
Preventing Future Outbreaks
Prevention starts in the fall. By managing how your lawn enters the winter dormancy period, you can significantly reduce the risk of mould developing under the snow. 1.
1. Manage Your Mowing Height
Long grass tends to mat down under the weight of snow, trapping moisture and creating the perfect breeding ground for fungus. For your final mow of the season, cut your grass shorter than usual, typically around 2 to 3 inches. This prevents the grass from falling over on itself and improves airflow.
2. Clean Up Fall Debris
Leaves left on the lawn create a wet, decaying blanket that insulates the fungus and keeps moisture locked against the grass. Thoroughly rake or mulch leaves before the first snowfall to remove this food source and shelter for mould spores.
3. Choose Resistant Grass Types
If you plan to overseed your lawn, choose grass species that are less susceptible to disease. Fine fescues and Kentucky bluegrass are generally more resistant to severe snow mould damage compared to creeping bentgrass or annual bluegrass, which are highly susceptible.
How Long Does Snow Mould Last?
The good news for homeowners is that snow mould is typically a temporary issue. In most cases, snow mould lasts only a few weeks and resolves on its own once the lawn dries out and temperatures rise above 45°F.
However, the exact duration depends heavily on weather conditions and the specific type of mould infecting your turf. While some outbreaks disappear quickly with the arrival of spring sunshine, others can persist if cool, wet weather continues.
How to Get Rid of Snow Mould
While the active fungus dies off as the weather warms, the damage it leaves behind often requires manual assistance to heal. The most effective way to get rid of snow mould is to mechanically break up the matted grass layer to restore airflow.
1. The Critical Step: Raking
Raking is the primary abatement method for snow mould. By lightly raking the affected areas, you break the “crust” formed by the fungal mycelium and dead grass tissue. This allows oxygen to infiltrate the soil surface and dries out the remaining moisture that the fungus needs to survive.
Important Warning: Timing is everything. Do not rake while the lawn is still soggy. You should wait until the moisture has largely subsided and you can walk on the lawn without it feeling “squishy” or leaving deep footprints. Raking too early on wet soil can tear up healthy grass roots and cause soil compaction.
2. Spring Fertilization
Once the lawn has been raked and is dry, a light application of nitrogen fertilizer can help the grass outgrow the disease. Since the roots are often still intact (especially with Gray Snow Mould), a boost of nutrients encourages rapid new leaf growth that pushes through and replaces the damaged tissue.
Will Snow Mould Go Away on Its Own?
While it is often a cosmetic issue that resolves as temperatures rise, assuming it will simply “go away” without intervention can lead to prolonged damage, especially if the fungal infection attacks the root system.
The short answer is yes – snow mould activity typically stops once the environment dries out and warms up. However, the recovery of your lawn depends entirely on the severity of the infection and the steps you take to help it breathe.
How to Prevent Snow Mould Next Winter
Preventing snow mould starts months before the first snowflake falls. The disease is most prevalent in depressions or low areas where snow piles up and melts slowly, creating the perfect wet, airless environment.
- Fall Cleanup: Leaves left on the lawn create a wet blanket that traps moisture and encourages mould. Mulching or removing leaves in the fall is essential for prevention.
- Mowing Height: Grass should be cut shorter (around 2-3 inches) in the late fall to prevent long blades from matting down under the snow.
- Grass Species: Certain grasses are naturally more resistant. Kentucky bluegrass and fescues tend to be more resistant to severe damage. In contrast, creeping bentgrass and annual bluegrass are highly susceptible to snow mould injury.
The Bottom Line on Snow Mould Eradication & Prevention
Snow mould looks worse than it is. It may look alarming when the snow first recedes, but it is rarely a disaster for your lawn.
By raking the matted areas to improve air circulation and applying a little spring fertilizer, your grass will likely recover fully on its own.
Focus on good fall cleanup practices to keep it from coming back next year.
