By the end of yet another Minnesota winter, you might be asking yourself how you survived. What’s even more impressive is how your lawn survived. Imagine spending every blizzard, cold snap and windy night left out in the elements. It’s pretty amazing what cool-season grasses can endure – well, usually endure. Although most varieties of turfgrasses in the Upper Midwest are hardy, they can still die under certain circumstances. Enter winter kill in grass, which is what occurs when grass dies due to abiotic factors or disease.
Read on to learn how to restore your Minnesota lawn from winter kill.
The Main Causes of Winter Lawn Damage
There are four major risks to be aware of:
Thirsty Lawns
Desiccation happens when the crown tissue in grass loses more moisture than it takes in. In the winter, a lack of snowfall is the main cause of desiccation. Without a layer of snow, the grass is exposed to dry winds that sap up moisture. Desiccation is a type of abiotic stress that turns lawns brown and thins the turf canopy. Grass can usually survive this damage, but newly seeded lawns are more vulnerable to death. Grass that is elevated and exposed to winds is more susceptible to desiccation. Windbreaks and snow fences can help prevent damage to lawns.
Temperature Drops
Direct low temperature kill is a phenomenon that occurs when early winter cold snaps follow a warmer-than-average fall. In late fall, grass usually undergoes a transformation that prepares it for the winter. The plant increases cellular solutes, which allows it to withstand freezing temperatures. If warm weather stays longer than usual, the entire process is delayed. Any sudden temperature drop can lead to ice formation in the plant’s crown tissues. Seasonal weather is tough to predict, but you can protect your lawn by seeding vulnerable species late in the summer. That way, they have more time to adjust to changing temperatures.
Ice Coatings
When a lawn is covered with a thick layer of ice, it can suffer what is known as ice encasement. The grass dies due to a limited exchange of air with the atmosphere. Semi-dormant grass is depleted of oxygen and toxic gasses begin to build around the plant. In a matter of weeks, the grass can die. There are many factors that determine how long grass can survive under a layer of ice. After about a month of consistent cover, it’s probably a good idea to remove the layers of ice. This can be done with aerators, black sand or hand tools. Be careful not to damage the lawn in the process!
Cracked Crowns
The most common type of winter lawn damage is crown hydration. Rapid freezing and thawing late in winter cause the issue. When temperatures rise above freezing for several days, grass crowns begin to hydrate. If there’s a sudden freeze after the thaw, the water can freeze within the crown. The ice causes the cell membranes to rupture, possibly killing the grass. Areas with poor drainage are more susceptible to crown hydration. It’s difficult to predict when and where crown hydration will occur, but improving surface drainage can help prevent any unwanted surprises.
Post-Winter Lawn Care Tips
On the other end of winter, your grass won’t necessarily reappear vibrant and green, but instead it will be brown, some of it dead from winter kill. Not to worry. Most of your grass is likely dormant, and it should be given time to start turning green again. To get your lawn prepped for spring, do the following:
- Rake your lawn. A light raking, when the ground is no longer frozen, will help the grass blades stand up and increase their exposure to sun.
- Irrigate properly. Once the weather is warm and your lawn has dried out, turn on your irrigation system to help your grass start to recover from winter dormancy. Be sure not to turn on your irrigation system until you know the ground won’t refreeze.
- Feed your lawn nutrients. Fertilize to help sprout growth as you head into the warmer months.
- Give your grass a trim. Once your grass has recovered from winter and grown at least a few inches, go ahead and give your lawn a trim. However, you don’t want to cut too deep, too soon.
- Deal with dead patches. As spring sets in, you may notice some small patches on your lawn that remain brown. These winter kill spots are usually circular and should be removed. Detach and overseed or lay down new sod in these areas.
If you suspect that you have any winter grass damage, contact our Twin Cities-based experts for a free consultation. We can assess the situation and determine the exact cause of the problem. In Minnesota, the climate is out of your control. What you can control is how you respond to problems with your lawn. Ensure that you have a beautiful green lawn when spring arrives!