There are many reasons why mowing wet grass is not a good idea, and it’s not just heavy rainfall that is a problem. Lighter rainfall is enough to create less than ideal lawn mowing conditions. While early morning mowing will fit well into your schedule, the dew on the lawn is enough to make it a huge mistake for your landscaping.
Cutting wet grass can damage your lawn
For an ideal cut, the blades of grass should be above the ground. Wet blades of grass are heavier than dry ones. For this reason, such blades nestle against the ground. If your lawn begins to dry out after a rain, some of the blades will return to their upright position and chop off as you mow, but the rest will not stand straight and your mower will drive right over them instead of cutting you. When they reappear, your lawn will be covered in “cowlicks”.
The resulting uneven look would be bad enough, but if you try to cut damp grass, the result is a crack rather than a clean cut. These cracks open the door for fungus and moisture provides a medium for fungus to spread. So when you mow a wet lawn you create a perfect fungal storm.
Fungal diseases can also develop on a lawn that has been mowed through the clippings after a rain shower and, under such conditions, form larger clumps. These clippings become matted downwards and impede a healthy flow of air. Excess clippings that fall on your lawn can lead to a fungal disease known as a “brown spot”. The wet clippings of grass that stick to the underside of the mower – if allowed to stay there – invite mold to grow, which can then be spread over your lawn.
After all, even simply going up and down a wet lawn with your machine can damage your lawn. The wheels sink into a damp surface in such a way that they won’t if the ground is dry. In the worst case, the wheels will create ruts in the surface that will damage the grass directly. In the best case, they lead to compaction of the soil, which over time leads to damage.
It’s not good for your mower, either
Moisture is a problem for the gasoline in the mower’s fuel tank, its metal parts and, indirectly, its engine. If you don’t mix a stabilizer in the fuel tank, moisture ingress will cause corrosion. Damp grass clippings that stick to the underside of the metal can eventually lead to rust. Even in the short term, the presence of this encrusted substance puts a strain on the engine – it hinders the movement of the blade, and your engine works harder to compensate for this.
Most of all, it’s unsafe
Your personal safety must always come before any work is done in the yard and you are at a higher risk of injury when mowing wet grass than when mowing dry grass. There are two factors that can increase your risk:
- Using an electric mower
- Mowing on the slope
One way to eliminate the latter is to grow ground cover on slopes instead of grass.
Regardless of the terrain and the type of mower used, there is a certain risk of slipping on smooth lawn. It can easily cause you to pull a muscle, but even a broken bone can’t be ruled out. The worst scenario is that if you lose control of your body in slippery conditions, one of your limbs will fall in the path of the rotating blade.
Mowing a wet lawn creates extra work
Mowing a wet lawn takes more time and effort, and because your lawn still doesn’t look very good afterwards, you should mow again as soon as possible. Also, wet grass will stain your clothes, shoes, and any surface your shoes touch, making it worse to clean up afterwards. However, all of this is just the beginning of the extra work, mostly in the form of any adjustments you need to make compared to normal mowing.
In case you have to mow when the lawn is wet
Sometimes you will feel compelled to cut the grass even though it is wet and with full knowledge of all the reasons why mowing is problematic at such a time. For example maybe:
- Your area has had a longer period of rain and more rain is forecast, and you know that waiting longer to mow it would mean the grass is going to be much taller than it should.
- You put your property on the real estate market and you are showing it today, and your garden needs to be aesthetically perfect.
Yes, you can mow in such cases, if you really have to, as long as the ground isn’t downright muddy – you shouldn’t sink into it or stand in puddles – but you should make some adjustments:
- Add stabilizer to your gasoline.
- Sharpen your mower knife safely.
- Raise your mower wheels; Mowing higher than normal will put less stress on the engine.
- Don’t try to mulch or bag the grass (if the lawn is wet, mulching won’t work as well and the inside of your bag will get horribly dirty): just empty it through the side chute.
- With each pass, you are only making half the swath that you would normally make when mowing. That way the engine doesn’t have to work as hard.
- Safely clean the underside of the mower deck and the discharge chute while driving so that less clippings stick to it (spraying silicone on a clean mower deck makes it easier to scrape).
- Then rake up the clippings and place them in your compost bin.
You can also be proactive. Listen to the weather forecast to stay informed of upcoming rain showers. If you know someone is coming, mow your grass before it can get wet, even if it isn’t usually time to mow.