The question “Why is my lawn mower spitting out grass?” will surely be running across the minds of gardeners who encounter this for the first time. It is normal to worry about grass flying in all directions while cutting grass on the lawn.

Why Is My Lawn Mower Spitting Out Grass

Mostly this could be due to faulty or clogged mower parts or because you are cutting wet and long grass. Read on as we have compiled all the reasons causing this problem along with their potential solutions.

Why Does Your Lawn Mower Spit Out Grass?

Your lawn mower spits out cut grass pieces that begin flying around during mowing because you are cutting grass that is too long or wet, using dull mower blades, or there is a blocked grass chute. Other reasons include a dirty mower deck or the grass bag being loose.

Find out even more reasons in the list that we have compiled below.

– The Grass Might Be Too Long

Allowing grass to grow too long can be problematic for the lawn mower. These long blades often get stuck in the blades of the mower and the mower deck. The poor machine will have to exert double the effort and start spitting out grass clips.

Long grass continually clogs the mower blades, and you will have to keep stopping again and again to clean it. It will take a lot longer to cut tall grass and then later to clean the grass clippings from the lawn.

– Your Grass Might Be Too Wet

Mowing wet grass with any machine is never a good idea, generally. The wet grass clippings get clumped together and are spat out by the mower. These clumped-together clippings also become stuck to the mower blades and slow down the working of the blades.

This might not harm your mower but it uses more energy than usual. Wet clumps are also spat out into the mower deck and become stuck. After each mowing session, cleaning the deck will take you twice as much time. The grass that is spit out will also form clumps on the lawn, and you must clean it with double the effort.

– The Blade Is Blunt and Dull

The problem with a dull and flattened mower blade is that it needs to cut grass evenly. Mower blades are designed to spin and create a suction that pulls the blades straight up. This helps cut the grass faster and more neatly.

Reasons Lawn Mower Spitting Out Grass

When the blade is dull from frequent use without sharpening, it will cut unevenly. Uneven pieces of cut grass are thrown around more than even grass. The suction created by the blades is also insufficient; hence the clippings are spat out instead of being collected in the collection bag.

– The Mower’s Grass Chute Is Clogged

The grass chute is a pathway through which the grass clippings are redirected into the bag in which they are collected. A clogged chute will redirect the cut grass toward the mower blades.

There are many reasons a chute gets blocked up and spits grass. The main reasons are cutting grass that is very tall or still quite wet. Sometimes, when the grass is being mowed extremely low, it can kick dirt into the chute and block it.

People who rarely clean their mowers will also face this problem because their unclean decks will end up choking the chute.

– The Mower Deck Is Dirty

We have said this before, and we will say it again: you need to clean the mower decks on the underside of your mower regularly. The cut grass pieces and dirt and soil are continually stuck there and form a thick carpet of debris.

If you go years without ever cleaning the underside of the mower, the deck will eventually have no more space and will start spitting out grass. You need to turn the mower over and see if a layer of grass has adhered to it.

– Grass Bag Under the Mower Is Wet or Loose

See that bag under the mower collecting all the cut pieces of grass? This grass bag might be responsible for all that grass being thrown around. This might happen if this bag becomes wet or gets contaminated with moisture. This contamination occurs mostly whenever someone uses the mower on a wet lawn or during a downpour.

When this bag is not attached properly and just loosely hanging under the machine, grass will spin around instead of being collected into the catcher bag. It would help if you ensured that this bag was dry and properly attached before each use.

– The Tires Are Under-inflated

When one or more mower tires are underinflated, they will lose their balance. The cutting blade present underneath also gets tilted. Imbalanced blades will always cut grass unevenly and get spit out more than ever. You can easily tell when the tires need to be filled with air again by looking or tapping at them.

– Air Filters Are Dirty

A lawn mower spitting grass might be due to a dirty air filter. The main function of air filters is to clean and filter out the air and exhaust. This filter gets covered by dust, debris, and grease over time.

If this carries on for too long, the proper working of your mower will be seriously affected and it will start spitting out grass. Regularly cleaning the air filters is an important aspect of lawn mower maintenance, and you must be vigilant.

How To Stop Your Mower From Spitting Out Grass?

To stop your push-type or riding lawn mower from spitting out grass easily, you should fix any problem with them and take regular lawn mower maintenance very seriously.

Solutions Lawn Mower Spitting Out Grass

Make sure to mow the grass only when it’s dry and sharpen the mower blades well.

– Mow the Grass Only When Dry

Make a mental note to always cut your grass when it is as dry as possible. This means no more mowing right after rainfall. Wait for at least one to two days after each rain spell, as this is how long it takes for grass to dry up properly.

The grass might dry up quickly if you live someplace hot and sunny. Refrain from watering your lawn a day or two before you plan on mowing it. Watering the lawn right after mowing is beneficial in more ways than one.

While mowing early in the morning might seem like a good idea, the grass is usually not dry at this point. Allow the sun some time to evaporate the dew drops present on grass blades, and then take your mower to it.

– Sharpen the Blades Well

Every time you cut grass, you need to clean the blade afterward. Most mower companies suggest that a blade needs to be sharpened after approximate use of every 20 to 25 hours. How much you use your machine will determine how often you need to sharpen it.

Always turn the mower off and disconnect the spark plug to prevent it from starting accidentally while your hand is near the blade. You should also drain the oil tank and store that oil for a refill later. Very carefully tilt the mower on its side but in such a way that it is stable and will not fall over.

Loosen the nuts or bolts to remove the blade from the mower, keeping in mind which side is up and which is down. Clean the blade off any debris using a dishwashing soap solution first. The easiest tool to sharpen a blade is an electric angle grinder.

Keeping it stable, sharpen it at an angle of no more than 45 degrees. Ensure that both sides of the blade are well-balanced before reinstalling the right side.

– Clean the Clogged Chute

Turn the mower’s power off and disconnect its spark plug to be safe. If it is an electric mower, then turn its power off beforehand. The mower parts that catch grass underneath the mower are easily removable by hand.

Next, lay the mower on its side with the fuel tank facing upwards to gain access to the deck belt containing the chute. You must use a hose to clean the stuck grass and debris from the mower deck and the blade.

Use a stiff straight brush with a long handle to reach the chute. With the help of this brush and the water hose, clean the chute. Clean the grass catcher bag and allow everything to dry before reassembling the mower.

– Clean the Mower Deck

Ensure the spark plug is disconnected and the switch is turned off before turning the mower over to its side while keeping it balanced.

Use a water hose and soap water to clean the deck until it is spotless. If the layer of debris is too thick to be removed with even pressurized water, then use a gardening knife to scrape it off. Allow the entire deck to dry well before you start the engine again.

– Keep Your Tires Evenly Inflated

If any of your tires get deflated, refill them immediately. If you don’t have the refilling equipment home, take it to the nearby gas station instead. Take care that all the tires are filled at equal pressure; otherwise, the balance of the mower will again be disturbed.

– Clean the Air Filter

The great news is that you can clean your filter by yourself pretty easily. Put your mower to a halt and turn it off. It helps to disconnect the spark plug to ensure the machine does not start even by accident.

If you have trouble gaining access to the filter, refer to the machine’s instructions manual. It is covered by a shroud that must be unscrewed first and removed. Take the air filter out of the mower and see if it needs to be cleaned or changed. Some filters made of paper can just be cleaned by tapping them on a flat surface.

The foam air filter needs to be washed properly using soapy water. It will take a long time for this filter to dry properly, and you must wait all that time before reinserting the filter back in.

– Don’t Allow the Grass To Grow Too Long

Do you see how low the cutting blade of lawnmowers is located? These machines are designed to keep the grass at a particular length only. You must keep cutting your grass regularly to ensure it doesn’t clog your machine.

It is highly essential to keep an eye on the growth rate of the grass you are growing. Fast-growing grass types need to be cut several times per month during growth. Slow-growing grasses need to be cut much less often in comparison.

Why Does Your Lawn Mower Spit Out Grass


Let us end this guide on lawnmowers spitting out grass pieces by reiterating the most important points.

  • Never use your mower on wet grass or grass that is too tall, even if you have the larger riding type of mowers.
  • If the grass catcher is loose or wet, or the chute is clogged, cleaning it would stop the lawnmower from spitting out grass.
  • Keep the mower deck and the air filter regularly clean to prevent spitting.

Go through our list to determine why your mower is spitting grass out every time you take it out. We have also provided the easiest solutions so you don’t have to go anywhere else!

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