Although grass does not stop growing in winter, it grows so slowly when temperatures go below 40 degrees Fahrenheit that mowing your lawn between November and March isn’t necessary (scroll down to see the step you must follow if you need to mow your lawn during winter). On the other side of the spectrum – and in a different hemisphere – grass stops growing when temperatures rise above 120 degrees Fahrenheit.
The only time grass can grow normally during a typical Colorado winter is if a patch of grass were to receive several hours of reflective heat (from sunlight) each day from a nearby building constructed of aluminum or metal compound. So while you might not have to deal with your lawn in the coldest months, there are a few things you can do to make sure your lawn is lush and healthy when the spring thaw comes.
Caring for Your Lawn in Winter: How to Grow a Lush Spring Lawn
Can you mow wet grass?
Avoid it if you can.
Refrain from mowing in fall (and summer as well) after it has rained heavily. Attempting to run a lawnmower over a combination of wet grass blades and muddy soil will damage roots and cause blades to cut grass unevenly. In addition, mower blades often gouge wet lawns; this motion instantly kills grown and sprouting grass.
How long should the grass be at the end of the year?
Your last mowing job of the year should leave two-thirds of grass blades instead of one-half of blades (a normal summer cut length).
The area of a blade just visible above the ground is more vulnerable to the stress of cold weather than the roots, so make sure you leave enough blade protection overhead. The almost imperceptible, slow winter growth that occurs when temperatures are at least 40 degrees Fahrenheit will also add to blade length and provide additional protection against snow and cold. Be careful how you implement your winter watering plan so your lawn is lush and beautiful in the spring.
What if a rare warm spell occurs?
If a rare warm spell occurs in the dead of a Colorado winter and your lawn starts to sprout, don’t worry about cutting the grass.
As you know, the warm temperatures won’t last – but the extra growth will protect roots and lower grass areas. A two degree Fahrenheit (one-degree centigrade) rise in temperature doubles a grass blade’s growth rate by stimulating metabolic processes in the grass.
Can I walk on frozen grass?
Walking on frozen grass breaks the blades.
For a fresh, green, healthy-looking lawn in the spring, don’t allow anyone to walk on the grass when it is covered with heavy frost or ice. This crushes grass blades and causes damage to blades – similar to going over your yard with a two-ton cement roller.
Are Colorado lawns are susceptible to snow mold?
Yes they are.
This fungus develops underneath snow patches and causes lawns to die when the snow melts in warmer temperatures. Snow mold is recognizable by its pinkish-gray color and circular shape that usually remains under 12 inches in diameter.
Preventing Snow Mold
Mow your lawn to a length that allows the blades to stay upright before winter. This prevents the grass from compacting and encouraging mold growth. Don’t apply fall fertilizer too late in the year because it can also provoke snow mold growth. You can minimize the chance of a lawn suffering snow mold by removing fallen leaves and debris before it snows. Make sure the lawn receives the right amount of nitrogen fertilizer after the final mowing.
Mowing in Winter: Follow These Steps
If you really want to mow the lawn, proceed with caution. Do not mow when there is heavy moisture from snow and ice plus frigid temperatures. Your tender, green grasses won’t benefit from a trim in these conditions. Mow your lawn in warmer conditions. Make sure the lawn is dry, the temperature is over 40 degrees Fahrenheit, and that you set the lawn mower blades high enough to only cut one-third of the grass’ length. Mow if you must – but be smart about it!