Answering whether or not there will be freeze damage to your lawn this winter is almost impossible, since there are a few things to understand about how turf adjusts to freezing temperatures first. If your lawn has had a chance to become acclimated to the cold through a period often referred to as the “hardening-off” process, it has a much greater chance of surviving freezing temperatures. If the freeze occurs very quickly without giving the turf time to adjust, there is a greater chance that your lawn will suffer freeze damage.
What Are Cold Response Genes?
Through research, scientists have identified a group of genes called “cold response genes” that play an important role. These genes are activated when the temperatures are in the 32 to 50 degree range for a period of time—this determines whether or not the turf can tolerate freezing temperatures. If these genes do not become active, then the tolerance of your lawn to freezing temperatures is reduced. If a lawn is exposed to freezing after it has had a chance to become acclimated, then there is less freeze damage. In addition to the colder temperatures, the amount of light that the turf receives seems to play important role in the activation of these genes, which may be the reason why freeze damage to lawns is higher in shady areas.
What Happens When Turf Is Dehydrated?
A good deal of this tolerance is based on how the turf reacts to cell dehydration. During periods of freezing temperatures, the water that surrounds the plant’s cells will freeze. Through the process known as osmosis, the unfrozen water within the cells will move out of the cell into the area where the water is frozen. In essence, the cells will dehydrate. Once the water between the cells warms up again, the water will flow back into the cells to re-hydrate them.
When Does the Most Freeze Damage Occur?
The greatest damage to turf occurs during freeze/thaw cycles that can occur throughout the winter, but mainly in the late winter and early spring. If the temperatures warm up enough to thaw the water between the cells, than the cells will rehydrate. If the temperatures drop below freezing before the acclimation process occurs, then the cells can rupture.
For the most part, cool-season turf generally goes through the acclimation process every fall. The greater damage often occurs on warm-season grasses that are exposed to freezing temperatures without going through this process. For instance, a good deal of freeze damage occurred on warm-season grasses during last winter’s (2013 to 2014) excessive cold weather.
How Do I Prevent Freeze Damage to My Lawn?
Turf is a remarkable plant; it seems to be able to tolerate any number of stresses and usually recovers given enough time and care. It has been my experience that turf that is properly fertilized and cared for over the years will recover from many of these stresses faster than those lawns left to fend for themselves. Have additional questions about care for your lawn? Contact your local Spring-Green professional.
Here’s hoping your lawn survives what’s in store for the rest of this winter! Stay warm, friends.