| Key Takeaways |
|---|
| • Mulching cuts grass finely: A mulching blade lifts clippings with a stream of air and chops them several times under the deck before they fall back into the turf. • Most mowers can convert: A mulching blade and a mulching plug let many existing push or riding mowers recycle clippings. • Skip mulching sometimes: Avoid mulching wet grass, diseased turf, weeds gone to seed, or heavy leaf cover. |
Wondering what a mulching lawn mower is and how it works? A mulching lawn mower uses a special blade and deck to chop your grass clippings into fine pieces, then drops them back onto the lawn as free fertilizer instead of bagging them.
This guide covers what a mulching mower is, how it works, how it compares to bagging and side discharge, how to use one, and why mulching is good for your lawn and the environment.
Prefer to skip the mowing altogether? LawnLove’s lawn mowing service connects you with local pros who handle the job for you.
What is a mulching lawn mower?
A mulching lawn mower is a mower whose blade and deck are built to cut grass into fine pieces and drop them back onto the lawn, where they break down into free fertilizer. Push mowers and riding mowers both come in mulching versions.
Read more: Benefits of Using a Mulching Lawn Mower
How does a mulching mower work?
A mulching mower works by keeping clippings under the deck and cutting them several times before they fall back into the lawn. A stream of air lifts the grass into the blade, and a curved, high-surface-area mulching blade chops it finer with each pass.
“A standard blade is just a straight piece of metal with big wings. It sucks the grass up, cuts it once, and throws it out the side,” says Taylor Olberding, founder/co-owner at Heroes Lawn Care in Omaha, Nebraska. “A mulching blade has a curvy profile, a much longer cutting edge, and it keeps the clippings moving around under the deck so they get cut over and over.”
Like other mowers, it needs lift to hold the grass vertical for a clean cut. The difference is where the clippings go: back into the turf instead of out the side or into a bag.
Two blade types handle clippings differently:
- 3-in-1 (mulching) blades: Sometimes called “all purpose,” these let you mulch, bag, or side discharge.
- 2-in-1 (standard) blades: These only bag or side discharge the grass.
Can I use my current mower to recycle my grass clippings?
Yes, you can convert most existing mowers, both push and riding models, to mulch. Ask your lawn mower retailer or manufacturer whether you need a conversion kit, which usually includes a new blade and a plate (or mulching plug) to close the discharge or bag opening.
You can also just close the discharge chute or remove the bag. A true mulching blade does a better job, though, because it cuts smaller pieces that break down faster.
Mulching vs. bagging vs. side discharge
All three methods handle your clippings differently, and the right choice depends on your lawn and what you want from it. Here is how they stack up.
| Method | Best for | Drawback |
|---|---|---|
| Mulching | Feeding the soil and saving time | Not ideal for wet, diseased, or overgrown grass |
| Bagging | Diseased grass, weeds gone to seed, or a tidy finish | Adds time hauling and disposing of clippings |
| Side discharge | Tall or overgrown grass | Scatters clippings in rows and feeds the soil less evenly |
For most healthy lawns, mulching is the smarter everyday choice on push and riding mowers alike. Keep bagging or side discharge for the exceptions in the table above.
Read more: Bagging vs. Mulching Grass Clippings
How to use a mulching mower
In short, use it just as you would any other mower. Here are a few lawn care tips to make sure your mulching mowing sessions are a success:
- Don’t mow when it’s wet: The mower might not be able to cut the grass blades as finely due to the extra weight and tendency to clump. Also, the underside of your lawn mower will be covered in wet grass.
- Mow often: Follow the golden rule of mowing: Remove no more than one-third of the grass blade per mow. During peak growth, that usually means mow every 5 to 7 days so clippings stay short enough to break down cleanly. “Now, if your grass is really tall, just bag it. Don’t try to mulch it,” Olberding says. “You’ll choke the mower, you’ll lose your airflow, and you end up with big wet mats sitting on the lawn.”
- Mow at the correct height: This simple advice makes a big difference in your lawn. Each grass type performs best when cut at a grass cutting height.
The seasons also matter: Mow about 1/2 inch taller in the hottest months, and slightly shorter for the first and last cuts. Where it snows, mow low on the final cut to help prevent snow mold.
Ask your local Cooperative Extension office for the best seasonal advice.
- Consider your lawn density: A dense lawn may put extra strain on your mower. When you’re buying a lawn mower, buy one that has sufficient power for your needs. Don’t skimp in this area; you’ll regret it.
- Maintain a sharp blade: A sharp mower blade is a must. A sharp mower blade gives you a clean cut instead of a torn one, which can invite disease into your lawn. Use a file, a hand grinder, a bench grinder, or a sharpening stone attachment on your cordless drill to sharpen the blade.
How often should you sharpen your mower blade? It depends on the type of grass you have, how often you mow, and the density of your lawn.
Here’s an easy test: If you look at the tip of the grass blade and it looks torn instead of cleanly cut, it’s time. If you have a dense lawn with stiff-bladed grass like Zoysiagrass, you may need to sharpen your blade as often as once per month.
- Keep the deck clean: Hose off the clippings underneath the deck at the end of each mowing session. A buildup of gunk on the underside of the deck may prevent the clippings from circulating as well as they should. “Every two or three mows, flip it over and scrape out that caked-on grass. If it builds up, it blocks the airflow, and then it starts dropping clumps all over the yard,” Olberding says.
Read more:
Mulching matters
Mulching matters because mulched clippings feed your lawn and keep yard waste out of landfills. You may still wonder, “So, what’s the big deal about whether I mulch grass or not?”
As Chelsea Morris of High-Class Grass in Virginia Beach, Virginia, puts it, “I always recommend mulching your clippings into your lawn, because it replenishes the nutrients and just helps it all around.”
Olberding says it saves on fertilizer by providing much-needed nitrogen to the soil.
“Those small clippings break down fast. They can give your lawn up to a quarter of its nitrogen needs for the year,” he says.
Mulching, sometimes called “grasscycling,” has many benefits:
- Saves time (no more raking fall leaves)
- Saves money (free fertilizer, no garbage fees)
- Helps protect the environment (no grass clippings in streams or landfills)
- Reduces erosion (helps keep the soil in place)
Read more:
How to mulch leaves in fall
Yes, a mulching mower shreds dry fallen leaves into small pieces that break down into the soil, so you can skip the raking. Mow when the leaves are dry, and if they cover more than about half the lawn, remove some first so the pile does not smother the grass.
Read more: Is It Better to Rake or Mulch Leaves?
FAQs
Finely cut clippings from a mulching mower typically break down within a few weeks, feeding nitrogen back to the soil. Warmth, moisture, and a healthy population of soil microbes all speed up the process, while thick clumps from wet or overgrown grass break down more slowly.
No. Finely cut grass clippings break down quickly and do not build thatch. Thatch is a layer of living and dead organic matter between the grass and the soil, made mostly of roots and stems, not clippings. As long as thatch stays under about 1/2 inch, your lawn is fine.
No. While mulching works well for most routine cuts, you can switch methods whenever conditions call for it. Bag or side discharge when the grass is overgrown, after applying certain weed treatments, or when you simply want a cleaner-looking surface for an event.
Let LawnLove handle the mowing
A mulching mower keeps your lawn fed and your clippings out of the landfill, but it still adds another chore to your weekend. If you would rather spend your Saturday doing something else, LawnLove’s local lawn mowing pros can handle it for you.
They will keep your grass cut, your clippings recycled, and your lawn on the path to a greener, fuller future. Get a free estimate today and see what a pro can do for your lawn.
Read more: 8 Best Mulching Lawn Mowers of 2024 [Reviews]
Main Photo Credit: PublicDomainPictures.net
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