The end of winter is an exciting time of year. Homeowners become eager to get back outside after a long lull in lawn care duties—but even the most hopeful of hearts sink at the sight of dead patches of grass as winter fades away.
Snow mold is the turf disease responsible for these whitish-gray or pink patches in the lawn that are revealed under the melting snow. Although grass may not be growing in the cold of winter, that’s when snow molds become active.
What is Snow Mold?
Snow mold is a fungal lawn disease that strikes during the cold months of the year, particularly during times of extended snow cover. Indiana lawns are susceptible to two types of snow molds: Gray snow mold (Typhula blight) and pink snow mold (Microdochium patch).
Although many fungal lawn diseases are active when temperatures are warm, snow mold remains dormant in the form of sclerotia and is often undetected during summer months. In fact, these hard masses of fungal cells can withstand challenging environmental conditions and may remain dormant for many years until conditions are favorable for them to grow and attack a lawn.
When conditions are freezing or near freezing, that’s when snow mold thrives. Snow cover is required for gray snow mold to grow, but pink snow mold may form with or without snow cover. Both typically form radiating circular patterns of damage that range from 3”-12” in diameter. These small patterns may merge into larger areas of damage. You may notice an outer ring of white mycelium resembling cobwebs, which is the early growth stage of these molds. The inner circle will appear pink with pink snow mold and remain whitish-gray with gray snow mold. You may also find tiny black sclerotia masses in cases of gray snow mold.
Snow Mold Prevention
If you’ve been through an occurrence of snow mold, chances are you’ll want to prevent it from ever striking again. Here are some of the steps you can take to protect your beautiful lawn from snow mold damage:
- Consider resistant species of grasses. Although all types of turfgrasses are susceptible to both pink and gray snow molds, Kentucky bluegrass and fescues are the most resistant.
- Follow a balanced fertilization program. Particularly, excessive over-application of nitrogen fertilizer in the fall can create a favorable environment for snow molds to thrive. Our lawn care treatment programs are specifically formulated for Indiana lawns and can help prevent snow mold from occurring.
- Follow through on lawn care responsibilities. Don’t skip that final treatment of the year! During the late fall, keep mowing the lawn until it enters a state of dormancy. Also be sure to remove leaves, clumps of mown grass or any other materials like hay or mulch from the yard before snowfall. These materials retain moisture on the turf and provide insulation, which is exactly what snow mold needs to thrive while it feeds on your lawn.
- Prevent snow drifts or large piles of snow on the lawn. Areas where large amounts of snow are allowed to accumulate on the grass will become much more vulnerable to snow mold. These slow-thawing piles set the stage with the right moisture and insulation for a snow mold horror story.
- Be consistent with lawn care. In addition to a balanced fertilization program like ours, be as consistent as possible with maintaining a healthy mowing height and irrigation program. Never remove more than ⅓ of the total length of the grass—even if you’ve missed a mowing and need to “catch up.” This stresses the lawn—as does long periods without water. The healthier the lawn is on a consistent basis, the more resistant it will be to diseases.
- Give shady areas a little TLC. Snow mold is more common in densely shaded areas, mainly because shady areas take longer to dry out after the thaw. Consider taking steps to improve drainage efficiency in shady lawn areas, and certainly remove fallen leaves or other debris from these areas. Perhaps the kiddos should build Frosty in a more sunny spot of the lawn, as well.
How to Treat Snow Mold & Minimize Damage
When snow mold attacks, homeowners need to know the steps to take to minimize the damage and treat the affected areas. The Purdue University Cooperative Extension Service recommends against the use of fungicides on residential lawns, which are toxic and can also damage or kill turfgrass. However, immediate steps can be taken to stop the growth of snow mold and hasten the lawn’s healing process in lieu of fungicides.
In a nutshell, here’s our advice for how to stop snow mold: groom and resume. Groom your lawn by raking through the affected patches to loosen grass that has become matted. A mowing may also help to get more air circulating through the matted grass plants. After grooming, resume fertilization treatments to help restore the health of your turf.
In severe cases, snow mold may permanently damage grass plants—in which case establishment of new growth from seed may be necessary. If you’re unsure about the severity of a case of snow mold in your lawn, we can help you assess the damage and chart the right plan for recovery.
As always, we’re here to help you solve your lawn care mysteries. Although it may be the first suspect, snow mold isn’t the only factor that can leave you with dead grass after winter. We’ll help you properly diagnose any cases of post-winter damage to be sure your lawn gets on the road to recovery. Call us today toll-free at 877-963-3200, or receive a free estimate online. For more frost and snow-related yard tips, read here.