What Temperature Is Too Cold To Cut Grass?

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Lawn mowing is intended to enhance the natural grass aesthetic while stimulating lushness and better health in the grass. However, you’ll get the opposite results if you mow your lawn when the temperature is below the recommended threshold. Instead of lushness, your lawn will be uneven as some grass fail to grow.

Temperatures below 40°F (4.44°C) are too cold to cut grass. Grass photosynthesis blades become too brittle when temperatures drop below 40°F (4.44°C); therefore, mowing will damage these blades, killing the grass. Consequently, the grass will not grow as expected in spring.

In the rest of this article, I’ll discuss the lowest possible temperature you can mow your lawn and why you shouldn’t mow if it’s colder. I’ll also cover the signs you should look for that signify when it’s time not to cut your grass. Keep reading to learn how to keep your lawn safe and lush.

What’s the Lowest Possible Temperature?

The lowest possible mowing temperature is 40°F (4.44°C). Grass stops growing when the temperature drops below this temperature and enters the dormancy stage. Mowing grass in this stage causes more harm than good.

Grass dormancy is a state of inactivity whereby the grass stops growing to preserve energy. The blades become hard, brittle, and dry during this period. Any mowing will damage these blades, killing the grass.

Some signs that your grass is dormant include:

  • Dry blades
  • Brittle blades
  • Lack of growth

These are all signs that the grass is not actively growing and, as such, shouldn’t be mowed. If you absolutely have to mow your dormant grass, make sure to follow the tips here in this article.

Dew on Lawn
Photo 198400873 © Zdasiuk | Dreamstime.com

Temperature below 40°F (4.44°C) causes freezing in the grass. Frozen grass is brittle since all the water within the cells is frozen solid. Solid water (ice) in grass cells may be too heavy, making the blades brittle.

The cutting impact on brittle grass blades exposes the grasses to damage, weakening, and even death.

Why Not Mow if It’s Colder?

You should not mow if it’s colder to eliminate the stress that can significantly hinder the ability of your grass to recover and grow during the growing season. Moreover, you’re most likely to damage your grass’s photosynthetic blades when you mow when it’s colder.

Other reasons you should avoid mowing when the temperature is below 40°F (4.44°C) include:

  • To keep your lawn even. There are chances of killing some grasses when you mow when it’s colder. The result is uneven and shaggy lawn when the growing period comes. Only the safe grass will grow, leaving empty lawn space that the dead grass would have otherwise occupied.
  • To reduce the spread of diseases. Some lawn diseases, such as snow mold, are more prevalent when you mow in cold weather. The spores of these diseases are known to survive the winter and can infect your grass in spring when you start cutting again.
  • To reduce stress on your grass. Mowing in cold weather can be stressful for your grass. The blades are brittle, and the grass is dormant, so any mowing will damage the blades. The damaged blades cannot produce food for the grass, leading to weak, stressed, or dead grass.

Signs That Show When Not To Mow Your Lawn

Now that you know the temperature that’s too cold to mow grass, what are some tell-tale signs that it’s time to stop mowing your lawn?

Here are a few:

Frost or Snow

Snow forms when the atmospheric temperature is at 32°F (0°C) or below. This indicates that the temperature is already colder than the recommended grass-cutting threshold.

Once the snow forms, the temperature can drop even lower, exposing your grass to more damage.

Frost is another type of weather that can damage your grass. Frost occurs when the dew on your grass freezes into ice crystals. The thin layer of ice on your blades prevents water uptake and nutrients, causing the blades to turn brown and dormant. You don’t want to mow in such conditions to preserve your lawn.

The Grass Is Too Wet

Wet grass is not ideal for mowing. Mowing such grass is catastrophic, not only to the lawn but also to your lawn mower.

Apart from damaging your mower’s blade, wet grass can’t withstand foot traffic. The pressure from foot traffic will cause the blades to bend and lay flat on the ground.

When grass blades remain on the ground, they become susceptible to diseases and pests. The thatch (a layer of organic matter at the soil’s surface) will also increase, leading to other problems such as waterlogging.

The Grass Is Very Long

Long grasses in winter usually have leaves at the top. These leaves keep them healthy by trapping heat and moisture. The grasses will be damaged once you cut the leaves, and they’ll have difficulty recovering.

It’s also challenging to mow long grass because the blades can get tangled in the mower, damaging the engine.

The Ideal Time To Mow Grass

The best time to mow your grass is from 2:00 p.m. onwards. Late afternoon is the best time if you want to maintain your lawn health.

Morning is the worst mowing time since the grass is still wet from the morning dew. Mowing wet grass does more harm than good. Some of the associated risks include:

  • Clumping grass. When you mow wet grass, it is more likely to clump. The clumped grass can be a perfect environment for lawn diseases such as snow mold to thrive.
  • Spread of diseases. Wet grass is ideal for spreading lawn diseases. The spores of these diseases can attach themselves to your shoes or clothes and be transferred to other parts of the lawn.
  • Clogging your mower. It’s more likely for your mower to clog when you mow wet grass. The damp grass can block the air filter, blocking the engine from getting enough air.
  • Damage to the blade. Clumped grass can damage the blade since it’s difficult to cut. In most cases, you’ll notice that the blade becomes dull after cutting such grass.

Final Thoughts

It’s essential to gradually reduce your lawn mowing frequency when the temperature drops in the fall. You should stop cutting the grass completely when you notice that the temperature has dropped below 40°F (4.44°C). Mowing at such temperatures may lead to regrets in spring when your lawn fails to grow and lush.

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