Mowing grass when it is dry is usually best. Wet grass clumps on the lawn and clings to the mower blades. Mowing grass weighed down with water may result in an uneven cut. You also run the risk of creating ruts across the lawn from the weight of the mower. Despite the risks, you can mow when the grass is wet if you follow some simple guidelines to keep the lawn healthy.
Decide When to Mow
For the health of your lawn, you should mow one-third of the blade length. With occasional rain, you can typically wait until the grass dries, even if that means waiting an extra day or two. Periods of continuous rain make it more difficult to wait until the lawn dries. Mowing wet grass is often better for the lawn than letting it grow too long, advises Carol Seminara of Texas' Hill Country Master Gardeners. If you can't catch a break in the rain and your grass is getting long, mowing while wet is OK.
Prepare the Mower
Adjustments to your mower make it easier and safer to mow the lawn wet instead of waiting until it dries. Sharpening your blades before cutting wet grass makes it easier to cut. Clean the blades before you start mowing. Old grass and lawn debris add to the buildup that can happen with the new, wet grass clippings. The highest blade setting is best when mowing a damp lawn. Remove the bag or mulching attachment and use the side discharge option instead.
A test walk across the lawn before you start mowing helps you decide if you should proceed with the mowing. If the ground is completely soaked, you notice you're sinking or leaving impressions, it's best to wait for the lawn to dry out slightly. A slow approach with narrow passes helps you cut the damp grass. Plan your mowing pattern so the grass clippings go on the areas where you already mowed. A second pass with the mower later in the day helps break up clumps.
Wet grass is often slippery. The grass clippings add to the slipping risk. Wear shoes with traction to reduce the chance of slipping while you mow the wet lawn. If the mower becomes clogged with wet grass, you'll need to clean out the machine before you continue. Shut off the mower and let it come to a complete stop before you turn it over to clear off the clumps. A corded electric lawn mower poses an electrocution risk if the grass is wet. Wait until the grass dries if you only own this type of electric mower.