What Temperature Is Too Cold To Mow Grass?

What Temperature Is Too Cold To Mow Grass

Winter is fast approaching, and some areas have already experienced heavy frosts (and even snow!). In the various around-the-house preparations for winter (like collecting the piles of leaves from your lawn), it’s easy to forget about your lawn. So, perhaps frost has arrived, and you notice your lawn looks a bit rough. But can you safely cut it if the temperatures have already dropped below freezing, or should you retire the lawn mower to the shed?

We’re here to help – we put together a guide for navigating mowing during cooler temperatures (and whether it’s a good idea), so stick around to learn more!

Can You Mow The Lawn In The Cold?

As a general rule, you should avoid mowing your lawn in sub-freezing temperatures. In many cases, the grass has gone dormant, so it won’t actively grow throughout these times of the year. So, there won’t be regular growth that requires mowing for maintenance. 

How Cold Is Too Cold to Cut Grass?

Most grasses (depending on your grass type) will go dormant when the temperatures become too cold or too hot. They do this to protect themselves from the elements – it serves as a survival mechanism. When the grass enters its dormant state, it often turns brownish, appearing dead under the layer of frost or snow. 

For cool-season grasses, the dormancy period begins later in the season(around 45 degrees Fahrenheit), whereas warm-season grass enters dormancy at higher temperatures (approximately 65 degrees Fahrenheit). While there’s a clear difference between these two, and when they enter dormancy, the rules for mowing are the same. 

Once the grass goes dormant, you no longer need to cut it, as it’s no longer growing much. Temperature-wise, you should stop mowing your grass when the temperatures regularly dip below 40 to 50 degrees Fahrenheit. At this point, the grass is likely dormant and no longer growing very much, so mowing is no longer necessary. 

What Happens If You Mow Grass After A Freeze?

Mowing Frosty Grass

Once the temperatures in your area drop in preparation for the winter freeze, it’s best to avoid mowing. Mowing can be detrimental when the grass blades are covered in a layer of frost, and cutting the blades, even just a small amount, can lead to extreme damage. 

When you mow your lawn, you slice a portion off, leaving behind a “wound.” In the summer, your lawn can recover relatively quickly, as it has abundant access to sunlight, water, and warmth. However, in the winter, the grass has a tougher time recovering, and in some cases, it might not recover at all. 

So, when you mow the grass after regular frosts begin in your area, the crystals can penetrate the “wounds” in the cell walls, killing those cells. This results in dead brown patches, as the blades cannot recover. 

Should I Mow During A Warm Part Of The Winter?

Sometimes, winter might seem to be on its way out, giving way to the warmer temperatures of spring. However, less than a few weeks later, the temperatures drop again, pushing back the arrival of spring. While the temperatures are warm, you might notice your grass slowly begins to grow again. So, should you mow?

While it’s hard to determine whether the warm weeks are going to give way to spring or recede to winter, it’s best to wait on mowing until the warm weather is here to stay. So, avoid mowing unless the warm weather is predicted to stick around and freezing temperatures are a thing of last season. 

Should I Leave My Lawn Long Or Short For Winter?

Ideally, you should leave your grass at a healthy height that is not too short or long. For example, consider cool-season grasses in a snowy area. When you leave these grasses long, they create a barrier between the snow and the ground. This creates the perfect place for voles and other vermin to tunnel into this area under the snow. Throughout the winter, these critters can wreak havoc on your grass, as they often eat grass roots and destroy your yard. 

In addition, long grasses in the winter are susceptible to snow mold and other types of lawn fungus. So, it’s best to avoid leaving your grass too long in the winter, as it could be susceptible to pests and diseases. This ensures the snow can sink down to the soil instead of resting atop the long grasses, which helps prevent snow mold and other issues.

On the flip side, grass that is too short might go into shock throughout the cold winter months. Even in the warmer months, you should avoid cutting off more than ⅓ of the blade’s total height at one time. Avoid trimming the grass too much before winter. You can leave an extra half inch more than usual for additional protection, but don’t leave it too long or cut it too short. 

When Should You Start Mowing In The Spring?

Lawn in The Spring

Now that we know the best time to stop mowing in the fall, what about the spring? Like the fall temperatures, predicting upcoming weather can be tricky. The weather can abruptly turn from warm and spring-like back to the cold temperatures of winter. 

So, when it comes time to start mowing your grass, you need to be careful not to cut it too soon, as this could result in damaged and dead grass. Wait about two weeks after the final predicted frost to mow, as this will help avoid damage due to cutting too early. 

Since grass doesn’t grow much throughout the winter cold, you won’t need to mow. Once the temperatures rise well above freezing and your grass begins to grow vigorously, it’s time to start mowing again.