Snow Mold when the snow is “Lawn” gone

When the snow finally clears Grey Snow Mold becomes evident on the turf with a dramatic display
When the snow finally clears Grey Snow Mold becomes evident on the turf with a dramatic display

So why all the problems with snow mold this spring? The answer lies in my opinion with the weather last November. Even though you possibly did everything right, weather conditions set up for the perfect storm, especially if your lawn is clay soil based or you haven’t core aerated in a few years. The lawn was still growing when the early snows hit last year….followed by a long winter of snow cover. The lawn is the host and the disease we call snow mold was present waiting for conditions to be ripe. You see even though we as people are dealing in winter with frigid winds and cold….under the snow which serves as insulation the turf is in a wet humid dark environment with temperatures around or just above freezing….ideal conditions for snow mold. I went back to look and the first 10 to 15 days of November we had some days in the 50’s and 60’s. Mid November on we had wintery wet snow and the blanket caused a problem. Especially if you are a person who puts their lawn mower away based on a calendar as opposed to putting it away with a good short cut when it stops growing. The turf continued to grow and could not photosynthesize due to dark conditions. At that point the dormant snow mold had the “perfect storm” conditions to develop under the snow and persist until the snow finally cleared last week. In most cases a leaf raking with some sunlight and air will allow the lawn to recover. In serious cases where there is crown damage their may be dead grass where turf areas need to be re-seeded. It is a good reminder too in my opinion that if you have a clay based soil lawn that fall aeration is a good idea. It is also interesting to note that the fungus under the cover of snow produces a gas that can be toxic to turf leaves.

Matted turf and the grey mycelium appears as the snow piles clear
Matted turf and the grey mycelium appears as the snow piles clear
Some people startled by it's appearance describe it to look like "spider webs" all over the lawn
Some people startled by it’s appearance describe it to look like “spider webs” all over the lawn
Then add the damage from Voles actively shearing vegetation below the cover of snow and the brown clippings that have a mess!
Then add the damage from Voles actively shearing vegetation below the cover of snow and the brown clippings that remain…you have a mess!

The good news is in most cases a light raking with a leaf rake allowing light and air into the turf will eventual fix the problem and the lawn will grow out of it. Feeding and some over seeding when the soil get’s warm enough in April will also make the difference in recovery.


So what IS under all that snow and ice that has covered your lawn for months? Beer cans? Mole damage? Vole damage? Snow mold? Interesting alert yesterday from my friend Kevin Frank at Michigan State University. He was looking at the potential damage to the Poa annua on putting greens but is it possible some of that damage could carry over to our lawns?

Lawn and order
Lawn and order

His point was the ice storm of December 21-22 coating everything including any exposed turf in ice followed by the polar vortex and snow event after snow event to follow. This has created a continuous layered cover of snow and ice for months. Could some death of turfgrass occur due to oxygen depletion and toxic gas accumulation from soil microbial respiration? What about the layer of leaves you never removed from the lawn because winter started so early and you never got around to it? As they say in the industry “stay tuned” and I’ll keep you “composted”.

“Plant” ahead

Looking to create some new planting beds or landscape area in your yard? To avoid the back breaking work of digging up sod, or having to spray weeds, or having to rent a sod cutter, try this…..

Easy bed preparation using black plastic to “solarize” existing turf and weeds

The black plastic is pinned down with landscape fabric pins and the heat of the sun “solarizes” or cooks the vegetation growing below it. Leave the black plastic on for about a month. When the leaves start falling off the trees in October pull up the plastic. The turf and weeds below will be dead. Cover the area in leaves and till the soil. You now have a new landscape bed ready for landscaping. October and November are a great time to plant and come next spring you’ll be glad you’re so smart.

Arid on the side of caution

Not even the official first day of summer yet and we’ve already experienced summer in West Michigan…….twice! In March unusually warm weather got everyone thinking shorts and tank tops. Then hot dry weather the first half of June has toasted lawns and made it feel like it has been summer for months. The process has been tough on plants and lawns. Some trees and shrubs are still trying to play catch up and rebound from hard April frosts. Minimizing stress with some deep watering as they attempt to bounce back will be essential.  One to two inch deep mulch at the base and some deep soakings will help, especially for plants put in the ground last year or this spring.

How dry I am

Remember sprinklers are for turf and hoses are for landscape plants. Morning is the best and most efficient time to water. For lawns don’t worry about weed control during hot dry periods. Save the weed control for less stressful times. They might be the only green some have in their lawns. Raise the deck on your lawnmower and if you have to mow do it during the coolest parts of the day. You don’t want grass expending energy in trying to grow leaf surface for photosynthesis. If possible park the lawnmower until we get through this period of heat and drought. Taller leaf blades help shade the crown of the plant. If your cool season turf goes brown don’t panic. Turf can endure a few weeks of dormancy and bounce back when weather conditions normalize.

“Arid” on the side of caution and get that sprinkler out!

If heat and drought persist longer than 3 to 4 weeks then you’ll have to get serious about “lawn-gevity” and whet the lawn’s appetite for a drink. In general lawns and plants should get 1 inch to 1 1/2 inches of water per week. Last I checked a number of areas in West Michigan have only had between a 1/2 to 1 inch of natural rainfall in the past 4 weeks! If you’re irrigating set out some coffee cans to measure how you’re doing.

Are you “Shear”-ious?

I love ornamental grasses because they come in a great variety, are easy to grow, drought tolerant and give 3 to 4 seasons of interest. By sometime in April you should have your ornamental grasses cut back. You can divide them too if you haven’t done so for a few years and if you have the energy. With some homeowners I have noticed a problem the past few years which falls under the are you “shear”-ious category when it crops up.

I have had samples of turf brought to me the past few years like the one pictured here:

Pennisetum Ornamental Grass reseeding in the turf








When we have a mild fall and winter season here in Michigan we will get turf samples where Pennisetum ornamental grasses like Hameln or Moundry will seed in the turf. This causes panic for the home owner in spring as it begins to outgrow the desirable turf. Maintain your “composture” if this happens. Repeated mowings of the lawn will usually solve the problem as the ornamental grass will get exhausted and wear out as it is unaccustomed to repeated haircuts and a low profile. This is the best option because if you take the Roundup approach you will be doing some reseeding.

Remember this problem does not occur every year as we unfortunately do not have a mild fall and winter every year. I wish we did. If you have a lot of these ornamental grasses that adjoin a lawn area you might want to get “shear”-ious about cutting them back in late fall to limit seed distribution.