Why Mowing Wet Grass is a Bad Idea

By PropertyClub Team
Nov 22nd 2020
Can you mow wet grass? The short answer is that it's a bad idea and could damage your lawnmower. Let’s take a deeper dive into mowing wet grass and into why you should avoid cutting it whenever possible.

We all know the feeling: you’ve worked all week, and now it’s Saturday morning. Time to mow that shaggy lawn! But it rained the last few days, and the grass is all yet. Worse yet, afternoon storms are coming in, so the grass will be wet tomorrow, too. Now, you’re faced with a conundrum. Do you mow your lawn today and deal with the wet grass? Or do you let it go until next weekend? If you’re lucky, you could even leave work Tuesday and mow then.

Making this decision requires an understanding of what happens when you mow a wet lawn. In short, you should avoid mowing wet grass if at all possible. That said, there’s a time and a place where it might be necessary.

hash-markWill Mowing Wet Grass Ruin my Lawn?

Yes and no. Cutting a wet lawn is never ideal, for several reasons. To begin with, a good cut requires grass to be standing up straight. That way, the blades of grass are cut to an even height. After a hard rain, some of the grass blades will be standing up, and others will be matted down. This leads to a raggedy look, with uneven blades throughout the grass. It can also create cowlicks in your lawn, with ugly swirls instead of a clean, striped pattern.

Another problem with cutting wet grass is that it tends to tear the grass rather than slice it cleanly. This kind of ragged tear is a perfect entryway for fungus. A fungal infection can cause yellowing spots, and a bad infestation can ruin your entire lawn. Fungal infections don’t just come from ragged cuts, either. Wet grass clippings can clump up, trapping moisture and creating a perfect habitat for mold and fungus. Wet clipping in your mower deck can even get moldy, spreading spores all over your lawn the next time you mow. Is all of that really worth cutting your lawn a day or two earlier?

This is not to mention the damage that cutting a wet lawn can do to the soil itself. Running your wheels up and down can leave ruts, which can persist even after the ground is dry. This is especially common with riding mowers due to their heavier weight. Even if you don’t leave any ruts, you’re still compacting the soil, which makes it harder for moisture to penetrate in the future.

None of this to say that cutting wet grass will ruin your lawn. However, it won’t look as good, and it can cause damage if you do it regularly over time. In other words, it’s best not to make a habit of it.

hash-markWill Mowing Wet Grass Ruin my Lawn Mower?

Mowing wet grass won’t ruin your gas lawn mower, provided you perform proper maintenance. However, there are a few issues you should be aware of before you start trimming away. The first is blade sharpness. A dull mower blade is never ideal, but it’s especially problematic with wet grass. We’ve already talked about how wet grass is harder to cut cleanly. Why make it harder with a dull blade? Keep your blade sharp, and make sure to have it sharpened once per season at a minimum. This will ensure the cleanest possible cut on the grass in any conditions.

Another issue to consider is that moisture can cause engine problems when it gets into your fuel tank. It can cause corrosion inside the engine, and it won’t compress or combust the way gas will. You can alleviate this with a fuel stabilizer. That said, ethanol gas already causes trouble for small engines, and you should be using a fuel stabilizer anyway unless you have easy access to ethanol-free gasoline. So for most people, if you’re already handling your fuel properly, this is a non-issue.

Finally, wet grass will cake up underneath the mower more easily than dry grass. This caked grass can grow mold, which will foul up the inside of your garage or toolshed. It also retains moisture, which can cause your mower deck to rust from the inside out. To avoid all these issues, it’s essential to clean out your mower thoroughly after each use. Be careful when you do this. If you turn the mower on its side, make sure to leave the carburetor facing up. If the carburetor is facing down, you’ll flood your engine.

hash-markCan I Mow Wet Grass With an Electric Mower?

Under no circumstances should you mow your lawn with a corded electric mower. There are simply too many opportunities for unshielded wires or an extension accord connection to get wet. This could damage your mower or even electrocute you while you’re mowing.

A cordless electric mower provides a safer option since there are no exposed wires. However, cordless mowers don’t have enough power to cut through any kind of seriously wet grass. You’ll find yourself frustrated and bogged down, and you’ll spend more time cleaning the mower than you will mowing anything. Just stick with a gas mower for wet grass. It’s the safest, most effective, and least frustrating option.

hash-markHow Long Should I Wait to Mow Grass After it Rains?

There’s no set amount of time for how long you should wait to mow after rain. It depends on a variety of factors. The temperature, the relative humidity, and the amount of sunlight will affect how quickly your lawn dries out. The best way to be sure is simply to stroll through the grass and see if your shoes come out dry.

Of course, in some parts of the country, this may never happen during rainier times of the year. If your grass is perennially wet, remember the tips we’ve laid out. Stick with a gas mower, and choose a powerful model. Most importantly, keep your blades sharp, and stay up to date with cleaning and maintenance. This way, you’ll get the best possible cutting performance for your weather conditions.