Solved! The Great Debate on Mowing Wet Grass
Think a post-storm lawnmower run is no big deal? Often, it'll actually do more harm than good. Read on for the best—and safest—practices.
I’ve seen a neighbor mow the lawn in the morning shortly after sprinklers quit, but I was under the impression that this practice was ineffective when the blades are still wet. Is it actually OK to be mowing wet grass?
A: While there are some conditions under which it’s acceptable to run the mower after a rainstorm, generally speaking, you’re right. The timing is ill-advised, and here’s why.
Water and electricity don’t mix.
Using an electric lawn mower on wet grass—especially with an extension cord—runs the risk of electric shock. When the connections (not to mention any wiring just beneath worn or damaged portions of the cord) are exposed to moisture, that could mean damage to the machine and an electrocution to its operator.
Mowing wet grass poses a personal danger.
Just walking the slick lawn with enough force exerted forward to push the mower could cause you (the operator) to slip and fall too close for comfort to the mower’s blades.
Damp blades of grass can damage the mower itself.
Without the appropriate fuel stabilizer, for example, leftover fuel in the tank can be contaminated as a result of excessive moisture and even corrode your machine. Grass clippings themselves can also interfere with mower’s job by sticking to the equipment in clumps that block the vacuum or the blade itself. In either case, these blockages will force the machine to work harder until it shuts off if you’re not carefully cleaning as you go.
A wet lawn is notoriously difficult to mow.
Wet grass blades are slick and tough to slice, creating an uneven shred (at best) rather than the clean cut achieved on a sunny afternoon. Unless your mower’s blades are in peak conditioned, newly sharpened or replaced, it may even take two or three passes over the same patch of wet lawn to get even a fraction of the cut you’d get if the lawn were dry.
The work won’t stop with the cut.
Wet grass will require extra cleanup, with how clingy grass clippings get when you add water into the equation. And damp grass clippings that stick to a mower’s undercarriage can create a breeding ground for mold—and eventually a busted mower—if the machinery stays too moist for too long. Be sure to scrape the deck clean of those stuck-on blades as well as brush off the tires and wipe down the body of the mower. Then, turn your attention the spots stains left behind. Chlorophyll in freshly cut wet grass will cause more stains than what you incur on your average mowing day, so be prepared to remove grass stains from your clothes, shoes, and driveway right away.
If your wet lawn just has to be mowed, ensure that conditions allow for it—and that you take all of the safety precautions. First, test the lawn’s saturation. When standing on your lawn, you should not be able to sink into it nor see water rising around the edges of your shoes—mowing through so much water is out of the question. Without the presence of standing water, you could potentially tame your yard to some degree using a stabilized gas-powered mower with sharp blades. If you can, set your mower to side-discharge mode; though this leaves rows of cut grass on your lawn for manual bagging later, it will save you the mess of dealing with a mower bag with a wet interior. Finally, change your mower deck to one of the higher settings in order to cut blades to three or four inches long and no shorter. It’s tough for a lawnmower to get a close shave when working with a wet lawn, so cut it some slack if you want it to do its job as well as it can. Following these simple rules of thumb can keep you safe even while trying to keep up lawn maintenance in less-than-ideal conditions.