Can You Cut Grass After Frost? Here's why I wouldn't ...

Although most people know that a hard freeze is a signal to put the mower away for the winter, frost can sneak up on you long before this happens; leaving many people wondering if it’s safe for them to mow after a frost.

Frost does not necessarily mean it is time to put the mower away. However, homeowners should avoid mowing directly before or after a frost and wait for their lawn to dry completely before mowing.

Continue reading as we take a closer look at the phenomenon known as frost, how it can affect your lawn, and when you should or should not avoid mowing.

What Is Frost?

For most people, seeing frosted blades of grass glistening in the sun is a familiar sight; but what is it that causes this layer of ice?

Frost is a light coating of ice that forms on objects such as windows, plants, and lawns. It typically occurs when temperatures fall below 36 degrees and water vapors in the air encounter objects whose temperature is below 32 degrees. The moisture quickly freezes into a thin layer of ice. Although the month that you will begin to see frost will depend on where you live, almost every state in the US will see frost at some point during the winter.

Will Frost Damage My Lawn?

How the early morning frosts affect your lawn will depend on the type of grass you have and how well you cared for the landscape during the warmer months. On its own, frost is harmless as most grass types can adapt to colder temperatures.

However, because the blades of grass are technically frozen, they will be more vulnerable to breaking. You should avoid walking on and mowing grass that is covered in frost as doing so can damage the blades and cause them to be more susceptible to diseases. Additionally, the tiny ice crystals are sometimes sharp enough to cut grass and damage it that way.

Should I Mow Right Before a Frost?

So, you know that you should avoid walking on or mowing your lawn when it is covered in ice but is it safe to get in a quick mow the day before a frost is due?

Although it’s tempting to squeak one last mow in before the big freeze hits, mowing right before a frost is not a promising idea. When you mow your lawn, you are causing damage to each blade of grass, which is okay during the summer because your lawn receives the nutrients and warmth to heal itself quickly. When grass is cold or has become dormant, it lacks the ability to heal these wounds quickly, making it susceptible to moisture, fungus, and bacterial infections.

Should I Mow Right After a Frost?

Knowing when to keep mowing and when to store the mower away after temperatures have dropped to freezing is tricky. As a rule, you will want to avoid mowing while frost is present on the ground, or while the grass is still wet from melting ice. Additionally, you will not want to mow directly before a frost is forecasted. However, if temperatures are above freezing and the grass is dry, it is typically safe to continue mowing after a frost.

How To Prevent Frost Damage

Luckily, there are several ways that you can protect your lawn from frost damage, and you can find these tips and tricks listed below.

Some professionals say that watering your lawn before a frost can help protect it from damage. However, others say that you should not water your lawn when the temperatures are below freezing because the water will turn to ice. The verdict? If you are expecting frost, plan on watering your lawn the day before the frost hits.
Do not walk or drive on frozen turf and try to keep pets away from frosted grass.
Protect grass from cold winds by installing some type of windbreak.
When planning the layout for your landscape, try to avoid shaded areas where frost will sit longer because it is not allowed to melt in the sun.
Young grass is more vulnerable to frost damage than grass that has had a chance to form strong root systems. Keep new grass-covered as much as possible. However, it is worth noting that grass seeds can survive the winter by going dormant during the colder months.
Do not mow right before or directly after a frost, and especially not while frost is still present.
Avoid raking while frost is present.

When Should I Start and Stop Mowing?

Caring for a lawn can be tricky, and even seasoned homeowners often struggle to decide when to stop and start mowing. However, while there is no one definitive answer, there are signs that you can look for to guide you.

It should be noted, though, that where you live and the type of grass that you have will play an important role in determining when to put the mower away, and the right time for one person might not be the right time for you.

Signs That It Is Time to Stop Mowing

Soil temperatures drop and remain below 55 degrees for warm-season grass and 45 degrees for cool-season grass.
Trees have lost more than 50% of their leaves.
Frost will often cause warm-season grasses to enter dormancy.
The grass is growing noticeably slower or not at all.
The lush greens of your lawn start to give way to browns.

Once you start noticing frosty mornings, keep an eye on the soil temperatures. Warm-season grass becomes dormant when the soil drops below 55 degrees while cooler season grasses will enter dormancy at 45 degrees. Keep in mind that temperatures must remain low for a period to trigger grass to stop growing

Signs That It Is Time to Start Mowing

The flowers on certain trees are blooming.
The grass has woken from its brown, dormant state and become green again.
Your grass is noticeably growing and is at least 2—3 inches tall.
Soil temperatures have risen above 45 degrees for cool-season grass and 55 degrees for warm-season grass.
It has begun raining and snow/frost is non-existent.

Grass will begin to come out of its dormant state and start growing again when temperatures increase and remain above 40 degrees. A good rule of thumb is to watch trees start blossoming as they will only do so when soil temperatures have remained above a certain temperature. Make sure to rake up any dead leaves or mulch and avoid mowing while the grass is wet.

Can You Cut Grass After Frost? Here’s why I wouldn’t …