Can You Mow Wet Grass?

Mowing the lawn is a regular chore we’ve all gotten used to. If you’ve ever geared up to get the job done, stepped on the grass, and had your foot sink half an inch, then you might be wondering whether it’s still safe or practical to mow the grass when it’s wet.

You can mow wet grass, but it’s certainly not ideal. Wet grass clumps well, causing it to clog your blades, getting into the motor and, if present, the fuel tank.

Updated: July 12, 2024.

It’s certainly not ideal to mow your grass if you want to get the most out of your equipment, but as with most things in life, there’s more nuance to this question than a simple yes or no answer.

What Happens When You Cut Wet Grass?

It’s worth noting up front that, yes, a lawnmower is perfectly capable of cutting wet grass, but as is the case with a lot of equipment and tools, the question is not whether you can do something but rather whether you should.

For most lawnmowers, mowing wet grass is detrimental, negatively affecting the blades and motor. When the grass is wet, it clumps more readily, sticking together and latching onto the underside of a lawnmower.

When this happens, wet grass can clog up the blades, causing the lawnmower to be less efficient and consistent with those beautiful straight rows. Mowing in wet conditions can also cause a number of other negative effects, such as the following:

• Damage to the mower
• Poor cut quality
• Higher risk of injury
• Greater chance of developing ruts
• Greater danger of spreading fungal diseases
• Grass clumping and staining on your mower and property

Mower Damage

One of the biggest reasons you should avoid mowing when the grass is wet is to prevent damage to your mower. Wet grass clumps, causing large clippings to form blockages in the deck. The formation of these clumps can cause the lawnmower to become strained, potentially leading to an engine overheating.

At a minimum, you’ll have to clear out these annoying clippings from the underside of your mower to prevent damage. Doing so requires you to empty the gas can and remove the spark plug from the underside. Detach the blade to avoid injury and start removing the caked grass clumps using a putty knife, pry bar, or just gloved hands.

If you are using an electric (corded or cordless) lawn mower, wet grass can cause moisture to enter the mower and cause short circuits, damaging the motor, cables, switches, and, if present, the batteries.

Wetting the deck can help loosen the clumps to make removal a little easier, and an air hose is an ideal tool to blow off residue and keep your lawn mower nice and clean. You should ideally conduct regular deck cleanings as a part of your mower maintenance routine, but you’ll find yourself constantly needing to clean it out if you’re mowing wet grass.

The damage from clumped grass goes far beyond an annoying maintenance routine or an overworked engine. The clogged grass can get into the motor and potentially even the fuel tank for gas-powered lawnmowers, causing serious damage and usually stopping the mower from working entirely.

Poor Cut Quality

You may not realize it, but environmental conditions can significantly affect the quality of the cut on your lawn.
When a mower blade cuts wet grass, the mower blade doesn’t make clean contact with the grass, causing it to shred the grass rather than cut it cleanly. Poor cut quality makes for an unaesthetic look and can even weaken your grass over time.

It also affects the long-term health of your lawn, creating conditions that lead to lawn disease. As such, if you have the option to wait another day or two for the grass to dry out, it’s always better to do so to avoid encouraging the onset of diseases that damage your lawn.

Risk of Injury

Lawnmowers are such a common tool for most people that it’s easy to forget just how dangerous those spinning blades can be.

It just takes one slip on a wet patch of grass for a serious injury to occur, and consistent precedent warns that most mower-related accidents occur in unideal conditions.

Wet grass is a liability, plain and simple. Keeping your footing is much more challenging, especially on slopes, hills, and softer terrain, greatly increasing the risk of injury.

To avoid harm to yourself and others while operating a lawnmower, only use it when the ground isn’t wet and hazardous.

As a general rule, you should be wearing boots that provide good grip both to protect your feet from injury and to avoid slipping in the first place.

Your safety is more important than getting the job done in unsafe conditions, and waiting it out is always more ideal than taking unnecessary risks.

Also, if you are using corded electric lawn mower, all of the extra moisture can even cause short-circuits, causing damages to the lawn mower, but also potentially causing an electric shock the user - not very nice thing to happen.

A Greater Chance of Developing Ruts

No one wants to deal with ruts in their yard, and it’s certainly not a pleasant sight to behold. These ruts or grooves can occur when it’s been raining for a while, causing your soil to be saturated and sink under the weight of a lawnmower.

This occurrence is especially prevalent with ride-on mowers, which are much heavier, adding the weight of the rider.

Ruts are a nightmare to deal with, requiring you to fill them with topsoil and replant new sod or seed to get your lawn level again. Even if your lawn is well overdue for a cut, it’s best to wait it out that cut in the rain and risk developing ruts that will take weeks, if not months, to repair.

Greater Danger of Spreading Fungal Diseases

When grass blades are wet, they are more susceptible to damage from mowing. This damage often takes the form of bruised or torn blades, which can significantly weaken the grass and make it more vulnerable to pathogens.

Fungal spores thrive in moist environments, and a freshly mown wet lawn provides an ideal breeding ground. The combination of open wounds on the grass blades and the presence of moisture can accelerate the spread of fungal diseases like brown patch, dollar spot, and rust.

These diseases not only affect the appearance of the lawn, leaving unsightly patches and discoloration, but they can also hinder the growth and overall health of the grass.

Also, the act of mowing a wet lawn can inadvertently facilitate the spread of these fungi. Mower blades can collect spores and transfer them across different areas of the lawn, exacerbating the problem. Cleaning the mower blades thoroughly after each use is very important, especially when mowing in damp conditions, to prevent this cross-contamination.

Grass Clumping

Grass clumps are not good for your lawn. They not only create ideal conditions for the onset of mold and other nasty diseases, but they can also block the underlying grass from getting any sunlight, causing yellow or brown patches to pop up all over your yard.

Grass clumps can also stain your house, your driveway—pretty much anything it gets on, leaving unpleasant green stains all over the place that are difficult to get rid of. These wet clumps are a nightmare to get rid of, lead to disease, and are just plain ugly.

There is a rumor that mulching grass clippings makes it easier to mow during the rain, but this myth is simply untrue. You’re still going to have to clean the deck regularly, and the risk to your safety, mower function, and lawn health are all still in jeopardy whether you bag or mulch your grass clippings.

Bagging isn’t really a good option either since a big, smelly bag holding a ton of water weight isn’t exactly ideal.

When Can You Mow a Wet Lawn?

Mowing a wet lawn is not advisable, and if you have the option just to wait a day or two, it’s always the best decision you can make. There are, however, a few exceptions.

Morning dew doesn’t pose as much of a problem as rain-soaked grass, allowing you the flexibility to mow your lawn and avoid damaging it.

Just be sure to check how much rain your grass has gotten and see whether the ground is damp and soft. That’s your first indicator that the grass will clump and the lawn will develop ruts.

A light misting isn’t going to negatively affect your lawnmower all that much, although you may find it advisable to clean out the deck afterward to take care of any clumping before it starts to strain the motor or engine.

If you live somewhere that experiences frequent light rain, then you’re not likely to have extremely soaked grass that will clump easily, but you may have to do maintenance more than in other areas where the grass is completely dry.

As long as you stay safe wearing the proper safety equipment while handling the lawnmower, you needn’t worry about damage to your mower in extremely light rain conditions.

Saturation in the soil is the point at which you’ll start to get extremely clumpy grass, dangerously soft ground, and poor blade contact, resulting in icky green blobs, a greater safety risk, ruts, and poor cut quality.

What to Do When Mowing a Wet Lawn

Hopefully, you’re convinced that mowing during or shortly after heavy rain isn’t good for you, your mower, or your lawn. If the rain persists for a long period of time or you simply have no other choice, then here are a few tips to keep in mind to avoid stains and unwholesome blobs of clumped grass.

Raise Your Mower Deck

Whatever setting you usually mow on, raise it by another inch or two. Doing so will help reduce the volume of grass clippings that will clump in the deck and wreak havoc on your blades.

It’s a way to prevent your engine from overheating and protect your mower from less-than-ideal conditions. Use the lever or the adjustment nuts to change your mower settings.

Sharpen Your Blade

As mentioned, lawnmower blades have a harder time making a clean cut on wet grass, leading to clumping. The problem is exacerbated by a dull blade, which is why you should ideally sharpen your mower blades for the best results.

Overlap Often

It’s a good idea to overlap your stripes whenever you mow, but it’s an especially good practice during the rain. For best results, overlap each stripe by half, measured by the width of the deck. Doing so will not only give you a better cut, but it can significantly reduce clumping.

In rainy conditions, this additional step can save you precious time picking up green clumps of grass or cleaning out your deck.

Don’t Cross Driveways or Sidewalks

If at all possible, avoid crossing your driveway or going onto other hard surfaces. Grass clumps can and will damage them, causing those annoying green stains that you’ll have to deal with in the future.

Mow Slowly

Another important tip when mowing wet grass is to go slowly. Normally, you’d cruise along at a brisk walk, letting your mower handle the workload, but when the grass is prone to clumping, you want to take it a little slower to avoid placing too much strain on the blades and, therefore, the motor.

Raising the deck, overlapping your stripes, and mowing a little slower will all help reduce grass clumping.

Clean Up Your Equipment Afterwards

Once you’re done mowing your wet grass, you’ll likely want to clean out the deck and get any clumps of grass off the wheels. Make sure that it is safe to do so before accessing the deck and removing any clumps of grass using the appropriate tool.

Clear Away Clumps

Any clumps that you’ll inevitably create while mowing wet grass should be cleaned as soon as possible. Leaving behind clippings can kill the grass underneath, additionally increasing the risk of infection in the lawn.

A rake is a preferred tool to get rid of large grass clumps and dispose of them properly.

Getting Rid of Grass Clump Stains

Should you find you’ve got annoying grass clump stains on your clothes, then you’ll want to treat it sooner rather than later, since, when left untreated, a grass stain can become impossible to remove. Grass clump stains are protein stains and cannot be treated with bleach; in fact, bleach can only deep the stain.

To combat grass stains, you’ll need the following:

• An enzymatic stain remover
• Laundry detergent

Before you start, brush away all the dirt you can with a stiff brush. Afterward, follow the application instructions listed on the enzymatic formula to apply it to the stained area.

Scrub thoroughly with a brush and repeat until the stain is gone, washing your clothes as you would normally the following treatment.

Few Final Thoughts

As it turns out, you are able to mow wet grass, but it’s not ideal under most circumstances.

As well as posing a risk to your safety, it also damages your lawn, can stain your clothes, and decrease the longevity of your lawnmower. If it’s an option available to you, just wait out the rain and mow your lawn in a day or two.