Mulching vs. Side Discharge: What to Do with Lawn Clippings

leaves on grass with half of them mulched with a mulching lawn mower

The most common ways to deal with lawn clippings are mulching and side discharge. Some homeowners prefer one over the other, but what sets them apart? Let’s go over the differences between mulching vs. side discharge to find out how they’re different.

Neither mulching nor side discharge is necessarily better than the other. It all depends on what you want out of your grass clippings and how much effort you want to put into your lawn care.

What is mulching and what is side discharge?

While mulching and side discharge both leave clippings on your lawn, how they handle this is what makes them different.

Mulching your grass clippings involves chopping up the grass clippings into tiny pieces as you mow. Then, they fall onto the grass. This is possible because the grass clippings are kept under the mower deck for a longer period of time. So to mulch effectively, you’ll need a closed mower deck or a cover for any chutes.

Side discharge, on the other hand, spits out the grass clippings from the side of the mower as you mow. They are usually ejected several feet away.

Let’s go over the pros and cons of mulching first, then we’ll move on to the pros and cons of side discharge.

Mulching pros and cons

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✓ Pro: Free nutrients for your lawn

The number one reason most homeowners would want to mulch their lawn clippings is for the free nutrients. As mentioned above, grass clippings return nutrients to the lawn as they decompose. Mulching grass clippings helps because the tiny pieces of grass are easier to break down and get down into the soil where they decompose.

✓ Pro: Faster than bagging

Mulching is also faster than bagging. You cut down on the time needed to mow your lawn because you don’t have to stop to replace the bag and haul off the bag of grass once the grass catcher is full. If you want to learn more about how bagging grass clippings holds up to mulching, read our article here: Bagging vs. Mulching Grass Clippings.

✓ Pro: Safer than side discharge

Mulching lawn mowers are generally safer than side discharge, too. They’re less likely to hurl rocks out at fast speeds because of their closed decks. It’s still not ideal to hit a rock with your mower, but at least you don’t have to worry about the rock shooting out and breaking anything or injuring anyone.

✓ Pro: Clippings look cleaner

Homeowners who mulch their lawn clippings are less likely to have the clippings sit on top of their grass, making an unsightly mess. The smaller clippings are harder to see, even more so when they get down to the base of your turfgrass.

✗ Con: Not as clean of a cut

However, don’t think that mulching is automatically more aesthetically pleasing compared to side discharge. Some homeowners complain that mulching results in a less clean cut, at least compared to side discharge. Mulching mower blades cut slower than a side discharge mower.

✗ Con: Slower mow than side discharge

Since the blades cut slower, mulching while mowing also takes longer than side discharge. You have to mow slower because you want the mulched grass clippings to be spread evenly across your lawn. Going too fast will result in clumps of grass you’ll need to spread. It also strains the mower because it’ll have to mulch a larger volume of grass clippings.

✗ Con: Mower deck gets dirtier faster

Unlike side discharge, mulching keeps clippings under the mower deck so they can be cut up into tiny pieces. This combined with the fact that a mulching mower doesn’t expel clippings several feet away means that the mower deck gets caked with grass much easier, especially if the grass clippings are wet and long.

✗ Con: Can’t mow tall or wet grass

But all of that may pale in comparison to the fact that mulching isn’t ideal if you have wet and overgrown grass. Mulching mowers struggle to cut tall grass. Wet grass will clump together, so your mower may spit out clumps of grass – if it doesn’t choke, anyway.

Side discharge pros and cons

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Pro: Fastest way to deal with clippings

If you don’t have a lot of time on your hands, side discharge may be the better option for you. Side discharge is the fastest way to mow and deal with clippings. You don’t have to bag as you mow or wait for your mower to mulch the clippings. 

You also don’t have to worry about distributing the lawn clippings evenly as long as you mow at a steady pace.

✓ Pro: Cuts cleanly even if grass is wet or overgrown

Side discharge is also better if you need to mow an overgrown lawn or a wet one (although we don’t recommend it, check this article for why: Ways You’re Accidentally Damaging Your Lawn). Long or wet grass clippings are less likely to clog with side discharge; the force the mower exerts is strong enough to expel grass clumps, and they do not stay under the deck of the mower.

✓ Pro: Stripes better than if you mulched

Lawn stripe lovers are going to love side discharge, too. The clean cut you get with side discharge stripes better compared to the cut you get when you mulch. (Read our guide on How to Stripe Your Lawn if you want to learn more.)

✗ Con: Sends grass clippings and debris into unwanted places

Side discharge does have its downsides. It can send your grass clippings into places you don’t want them to be in, like your walls, driveways, sidewalks, flower beds, the road, or even your neighbor’s yard. You might even get fined for littering if you leave them on the road.

Side discharge will shoot out anything that gets under the mower, including rocks and other debris. This debris can hit something – or worse, someone – and break (or injure) them.

You do have options for controlling where your grass clippings get chucked, though. Here are some ways to manage discharge:

  • Operator-controlled discharge chutes (OCDC) can stop the discharge chute from shooting grass for a short while.
  • Chute blocks or block-off plates temporarily block off the side discharge chute. You can also allow the grass clippings to be discharged closer to the mower by changing the angle of the chute block.
  • You can also just change the direction where you mow to prevent the mower from discharging grass into unwanted places.

You also can consider rear discharge, which spews grass clippings from the back of the mower. It is generally better if you have a small yard with lots of landscaping, but it’s not as good against tall and wet grass.

✗ Con: Larger clippings are messier and decompose slower

Side discharge is not the best way to deal with lawn clippings if you want them to break down on your lawn. Long grass clippings decompose slower than smaller ones, and they won’t break down at all if they sit on top of the grass.

Aesthetically speaking, side discharge may be worse when it comes to the clippings themselves. Long grass clippings will be more visible and are more likely to sit on top of grass.

When to mulch vs. when to side discharge

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Given the pros and cons of mulching and side discharge, we can figure out when it’s better to use each method.

When you mulch your grass clippings, they fall on your lawn. The smaller clippings get down into the soil faster, so they break down quickly and nurture your lawn. However, you have to dedicate more time to mowing, both because mulching while mowing takes longer and because you have to mow more often. This may not be ideal during your lawn’s peak growing season.

Basically, you’ll want to mulch if you:

  • Have a small yard
  • Have a lot of free time to mow
  • Can mow often
  • Want a healthier lawn

On the other hand, you have side discharge which is the fastest way to handle grass clippings. It also trims your lawn neatly, even if it’s wet or overgrown. However, it won’t return as many nutrients to your yard, plus it can be messy if you have a smaller space.

So, you’ll want to use side discharge if you:

  • Have a large yard
  • Don’t have a lot of time to mow
  • Have a lot of rain in your area
  • Like to mow your grass when it’s tall

The good news is that you don’t have to choose between just mulching or just side discharge. Most modern lawn mowers can do both – some can even bag, too. You also can buy attachments (usually mulching kits) to add that functionality to your current mower. 

If you are looking the perfect mower, take a look at our reviews of the best lawn mowers on the market:

FAQs about mulching vs. side discharge

Should I even leave clippings on the lawn?

Both mulching and side discharge are excellent ways to grasscycle. Grasscycling is when you leave yard clippings on your lawn so they return nutrients back into the soil for your grass to use. According to the Michigan State University Extension Service, grasscycling can return as much as 1 pound of nitrogen per 1,000 square feet of lawn, reducing the need to fertilize.

If you’re worried about grass clippings worsening thatch production, then we have good news for you. Many experts stress that grass trimmings break down too fast for them to significantly contribute to lawn thatch. 

“Long clippings may contain wiry stem material that is slower to decompose, but are still not significant contributors to thatch buildup,” says the University of Minnesota Extension.

When should I not leave clippings on the lawn?

Here are the times when you should not leave yard clippings on your lawn:

  • Your lawn is sick. Diseased turf will yield diseased turf clippings, which can spread lawn diseases and fungi throughout the rest of your healthy grass. You can read our article about grass fungus to learn how to get rid of it.
  • You have a lot of grass clippings. Too much of a good thing can be bad, and grass clippings are no exception. Too much of the clippings can smother your lawn and leave brown spots.
  • Your lawn is new. Newly-seeded turf can’t handle the weight of the clippings.
  • Your lawn has excess thatch. Although the clippings won’t make your thatch problems worse, they won’t reach the soil. Clippings won’t reach soil microorganisms that break them down if the thatch layer is more than ½-inch thick, says the University of Missouri Extension.
  • You have a lot of weeds. While mowing, you may mow weed seed heads, which will contain weed seeds. If left on the lawn, the seeds will sprout and lead to even more weeds.
  • You have children or pets. The little ones may eat the clippings, which can make them sick. The clippings may also track inside after a good play session on your lawn.

What else can I do with lawn clippings?

Here are a few things you can do with the lawn clippings you can’t leave on the lawn:

  • Compost them. Your grass clippings are a great source of nitrogen. You can add them to your compost pile as a green waste material. Learn more about this in our guide: How to Compost Your Grass Clippings. Note: Don’t compost grass treated with herbicide.
  • Mulch them, but not on your lawn. You can use your lawn clippings as free mulch for your landscape beds, shrubs, and trees. Just make sure they haven’t been treated with herbicides.
  • Drop them off for curbside composting. Some communities offer curbside composting, where they take your grass clippings and turn them into compost.
  • Bag them and dispose. This is ideal for clippings from lawns that are riddled with weeds. 

However, you have to make sure that you’re allowed to throw away your grass clippings. The US Composting Council says these states ban or limit homeowners from throwing away yard clippings in the garbage bin:

  • Arkansas
  • Delaware
  • Florida (only allowed in landfills with gas collection systems)
  • Georgia (only allowed in landfills with gas collection systems)
  • Illinois
  • Indiana
  • Iowa (only allowed in landfills with gas collection systems)
  • Maryland
  • Michigan
  • Minnesota
  • Missouri
  • Nebraska (only allowed in landfills with gas collection systems)
  • New Hampshire
  • North Carolina
  • Ohio
  • Pennsylvania
  • Rhode Island
  • South Carolina
  • South Dakota
  • West Virginia
  • Wisconsin

Note: Some counties and municipalities ban this practice even if there is no state-wide policy on it. Always check with your local authorities

Hire a pro for a clean-cut lawn

Mulching is better for your lawn’s health, but side discharge is a much faster way to take care of grass clippings. However, sometimes you just won’t have enough time to mow your lawn properly even if you side discharge – especially if your grass is growing very fast. In times like these, we recommend hiring a lawn care professional to handle it for you.

Lawn Love can connect you with a lawn care pro in your area who can mow your lawn and take care of the clippings however you like. They can also fertilize your lawn, get rid of weeds, and much more, so you can have a beautiful lawn without lifting a finger.

Main Photo Credit: Mulched leaves, Famartin | Wikimedia Commons | CC BY-SA 4.0

Janine Caayao

Janine Caayao has always been fascinated with growing plants, from fruits and veggies to bonsai trees and orchids. Now, she’s interested in urban gardening with her family. She loves finding new tips and tricks to keep their plants thriving.