Snow Mold on Lawn: What It Is and How to Get Rid of It

By the YardClues editorial team · Updated

Snow mold is a cool-weather lawn fungus that shows up as the snow melts: roughly circular, matted patches of tan or straw-colored grass, sometimes covered in a grayish-white or pinkish cottony web. It grows under long-lasting snow cover, and in most home lawns the grass greens back up within a few weeks once you rake the patches loose and let them dry. Fungicides are rarely needed — fluffing the matted grass and fixing fall habits usually does the job.

Most likely causes

  • Gray snow mold — matted tan patches with a grayish-white web and tiny dark specks on the blades
  • Pink snow mold — smaller patches with a pink-to-salmon tinge around the edges
  • Vole runways — winding surface trails of clipped grass with droppings, not round patches
  • Road or driveway salt burn — a dead strip along pavement where salty snow was piled
  • Dog urine spots — round dead spots, often ringed with darker green grass

Not quite what you're seeing? Answer four quick questions and the clue finder will point you to a closer match.

Compare the possible causes

Possible cause Key signs When it happens How likely
Gray snow mold (Typhula blight) Circular, matted, straw-colored patches about 3–12 inches across with a grayish-white cottony web; tiny hard brown or black pinhead-size specks stuck to the blades Late winter into early spring, right as snow melts — especially after long snow cover on unfrozen ground Very common
Pink snow mold (Microdochium patch) Patches a few inches across, often smaller than gray snow mold, with a pink, salmon, or reddish-tan tinge at the edges; the web may look whitish-pink in damp mornings Snowmelt in late winter and early spring, but also during cool, wet spells in fall or spring with no snow at all Common
Vole runways Winding, 1- to 2-inch-wide surface trails where grass is clipped to the soil, often with small rice-shaped droppings and occasional golf-ball-size holes Exposed at snowmelt — voles travel under snow cover all winter Common
Salt burn from roads and driveways A brown strip of dead or thin grass running along the edge of a driveway, sidewalk, or street; no fungal webbing Noticed in early spring wherever salty snow was shoveled or plowed Common
Dog urine spots Round dead spots a few inches to about a foot wide, often with a ring of greener, faster-growing grass around the edge Builds up over winter in favorite potty areas; very visible at snowmelt Common

Visual clues to check

  • Look for round, matted patches of tan or straw-colored grass appearing right as the snow pulls back
  • Check the patch edges on a damp morning for a cottony web — grayish-white suggests gray snow mold, pinkish suggests pink snow mold
  • Pull a few blades and look closely for tiny hard brown or black specks the size of a pinhead — a sign of gray snow mold
  • Notice where the worst patches are: under old snow piles, in shady spots, or where leaves were left on the lawn
  • Trace the shape: round patches point to snow mold, winding connected trails point to voles, and a strip along pavement points to salt
  • Look for a darker green ring around a dead spot, which suggests dog urine rather than mold
  • Tug on the grass in the center of a patch — firm crowns mean it's likely to green up; crowns that pull out easily may need reseeding

The causes in detail

Gray snow mold (Typhula blight)

This is the snow mold most homeowners find. The fungus works slowly under a blanket of snow, then shows itself as the snow pulls back, leaving flattened, bleached patches that can merge into larger irregular areas. Those tiny dark specks are sclerotia, the fungus's resting bodies, and they're the easiest way to confirm it. Gray snow mold mostly damages the leaf blades rather than the growing crowns, so the grass usually recovers on its own once it dries out and starts growing.

Pink snow mold (Microdochium patch)

Pink snow mold doesn't need snow to get going — cool, drizzly weather is enough, which is why you may spot it in years with little snow cover. The patches tend to be smaller than gray snow mold, but it can be the more damaging of the two because it can reach the crowns of the grass plants. If patches stay brown and thin after the rest of the lawn has greened up, those spots may need overseeding.

Vole runways

Voles tunnel along the soil surface beneath the snow, grazing grass as they go. When the snow melts, the lawn is left with a maze of narrow, matted paths that some people mistake for snow mold. The difference is shape: snow mold makes round patches, while vole damage makes connected trails. Vole runways usually fill back in once the grass starts growing; rake out the debris and overseed bare stretches. See all voles signs →

Salt burn from roads and driveways

Deicing salt in plowed and shoveled snow soaks into the soil along pavement edges and dries out grass roots. The damage follows the line of the snow pile rather than forming circular patches. Flushing the area with plenty of water in spring helps wash salt below the root zone, and overseeding — with a salt-tolerant grass where the problem repeats every year — fills the gap.

Dog urine spots

Urine concentrated in one spot burns grass, and a winter's worth of visits in the same area shows up all at once in spring. The giveaway is the dark green ring around a dead center, which snow mold doesn't have, and the spots cluster where the dog actually goes. Water the area well and reseed bare centers once the soil warms.

When to worry

  • Patches are still brown and thin several weeks after the rest of the lawn has greened up
  • Pink-edged patches keep spreading during cool, wet weather in spring or fall
  • Snow mold returns in the same areas every spring, which points to a fixable habit like late fertilizing or snow piling
  • Large areas of the lawn merged into one matted mat with grass crowns that pull out easily

What to do now

  1. Wait until the lawn is dry enough to walk on without leaving footprints in soggy turf
  2. Gently rake the matted patches with a leaf rake to fluff the blades and let air and sun dry them out
  3. Spread out any lingering snow piles so the area underneath melts and dries faster
  4. Give it time — most lawns recover within a few weeks as the grass starts growing in spring
  5. Overseed any spots that stay truly bare once the soil warms, keeping the seed lightly moist until it sprouts
  6. If severe snow mold returns every year, talk to a local lawn care professional or your county extension office before considering fungicides, which are rarely needed on home lawns

What not to do

  • Don't rake hard or dethatch while the turf is soggy — you'll tear up grass that would have recovered
  • Don't leave wet, matted leaves or debris sitting on the patches — they hold moisture against the grass and slow recovery
  • Don't apply fungicide just because you see snow mold — on home lawns it's usually unnecessary
  • Don't keep piling shoveled or plowed snow on the same section of lawn every winter

Think you know the suspect?

These animals commonly cause this clue — see their full sign profiles:

Frequently asked questions

What is snow mold?

Snow mold is a group of cool-weather fungi that grow on grass under snow cover, especially when snow falls on ground that hasn't frozen yet. It shows up at snowmelt as round, matted patches of tan or straw-colored grass, sometimes with a grayish-white or pinkish cottony coating. It's common across northern lawns and usually cosmetic.

How do I get rid of snow mold on grass?

Once the lawn is dry enough to walk on, gently rake the matted patches so the grass blades stand up and dry out. Sun, air, and new spring growth take care of the rest in most lawns within a few weeks. Overseed any spots that stay bare, and fix fall habits — final mowing, leaf cleanup, and fertilizer timing — to prevent it next year.

What's the difference between pink snow mold and gray snow mold?

Gray snow mold leaves larger patches, about 3–12 inches, with a grayish-white web and tiny dark specks on the blades; it usually damages only the leaves, so grass recovers. Pink snow mold has a pink-to-salmon tinge at the patch edges, can appear in cool, wet weather even without snow, and can be more damaging because it can reach the grass crowns.

Can snow mold cause allergy symptoms?

As snow mold patches dry and get raked, mold spores can become airborne, so people who already have mold allergies may notice their usual symptoms flare. Raking on a calm day and wearing a dust mask can help limit exposure. If you have allergy concerns, talk to your doctor.

Will my grass come back after snow mold?

Usually, yes. Gray snow mold mostly affects the leaf blades, so the grass typically greens up within a few weeks of spring growth. Pink snow mold can occasionally kill the crowns in some spots, and those small areas may need overseeding.

How do I prevent snow mold next winter?

Keep mowing until the grass stops growing, with a final cut around 2.5–3 inches, and rake up leaves before the first snow. Avoid heavy nitrogen fertilizer late in fall, and spread out big snow piles from shoveling or plowing instead of stacking them on one part of the lawn.

Related yard clues

Lawn Problems Brown Patches in Grass: How to Read What Killed the Turf Brown patches in your grass are most often caused by fungal disease, white grubs eating the roots, dog urine, or summer drought dormancy. The pattern is the diagnosis: circles point to fungus, turf that lifts like carpet points to grubs, and small spots ringed with dark green grass point to dog urine. Read the guide → Lawn Problems Yellow Spots in Lawn: Urine, Fertilizer, or Something Fungal? Yellow spots in a lawn most often come from dog urine, fertilizer burn, lawn rust, iron deficiency, or overwatering. Scattered spots with green rings point to a dog; stripes or spots that match your spreader pattern point to fertilizer; orange dust on your shoes points to rust fungus. Read the guide → Yard Holes Tunnels in Grass: Mole or Vole? How to Tell in Seconds Tunnels in a lawn come in two distinct styles: raised, spongy ridges you can feel underfoot are mole feeding tunnels just below the surface, while flat, worn trails clipped into the grass itself are vole runways. Moles hunt worms and grubs under your turf; voles eat the grass and bark on top of it — so telling them apart decides everything about what to do next. Read the guide → Lawn Problems Lawn Dying in Patches Despite Watering? Find the Real Cause If dead patches keep spreading no matter how much you water, water was never the problem — something is attacking the grass or the soil beneath it. The most frequent culprits are grubs eating roots, chinch bugs along hot sunny edges, compacted or debris-filled soil, fungal patch disease, and dog urine. Each one leaves a distinct fingerprint you can check in minutes. Read the guide →

Still not sure? Compare with these clues

Yard Holes Moles vs Voles: How to Tell Which Is in Your Yard Moles are insect-eating tunnelers that push up volcano-shaped mounds and raised ridges but never eat your plants; voles are mouse-like rodents that make open surface runways and 1 to 1.5-inch holes and do eat roots, bulbs, and bark. The fastest tell: mounds and no plant damage means moles, while open holes, surface trails, and chewed plants or gnawed bark mean voles. Read the guide → Mushrooms & Growths Mushroom Rings in Grass: What a Fairy Ring Is Telling You A circle or arc of mushrooms in your grass is a fairy ring: a single underground fungus colony that started at one point and has been expanding outward ever since, fruiting mushrooms at its edge after rain. Fairy rings are mostly cosmetic and notoriously hard to eliminate — for the vast majority of lawns, the right plan is managing the look and removing the mushrooms, not fighting the fungus. Read the guide → Home Exterior Clues Does Salt Damage Concrete? Why Your Driveway Is Flaking Yes — salt can damage concrete, but mostly indirectly. Ordinary rock salt doesn't chemically eat sound concrete much; instead, the salty meltwater soaks into the surface, refreezes, and expands, popping off thin layers in a process called scaling. New concrete, concrete poured without air entrainment, and slabs with a weak, overworked top layer are the most likely to flake, pit, or crumble after a salty winter. Read the guide →