Understanding the Mulching Lawn Mower

what is a mulching lawn mower

Mulching your lawn is an excellent way to cut fertilizing costs and improve the health of your lawn. What is a mulching lawn mower? Find out everything you need to know about mulching lawn mowers, including how to use one and the benefits they provide.

What is a Mulching Lawn Mower?

The term “mulching” usually refers to spreading either wood or rubber mulch throughout landscaped areas. But, how does that translate to lawn mowers?

Well, manufacturers have specifically designed certain models to turn grass into mulch, so you’re essentially making your own compost. On top of that, it’s easy to learn how to compost using other nourishing organic matter, enabling you to augment the fertilizer that your mulching mower creates for you.

Of course, it doesn’t quite work the same way as mulch in a flower bed

Mulching mowers chop your grass into tiny pieces. This leaves behind nutrient-rich clippings that eventually break down and fertilize the soil. Furthermore, they help your lawn retain moisture throughout the hot summer months.

The Rising Popularity of Mulching Lawn Mowers

avoid bagging grass clippings by using a mulching lawn mower
Bagging grass is a hassle, and it’s eco-unfriendly, making mulching lawn mowers attractive options.

“Reduce, reuse, recycle” is a mantra you hear all the time, and many are even applying this eco-friendly principle to their lawn care practices

Using a mulching mower to recycle your grass clippings keeps them out of landfills. Moreover, it reduces the need for lawn treatments. This makes a lot of sense for many homeowners, hence the rising popularity of such models.

So, now’s a good time to explore how a mulching mower works, as well as how to choose the best mower for your lawn.

How a Lawn Mower Mulches Grass

Blade and Deck Function and Design

Now comes the million-dollar question: How does a mulching lawn mower work?

The short answer is that it’s all in the blades, which are different from those you find on standard models.

Mulching blades have multiple cutting edges and a gently curved design. This shape makes the air swirl inside the mower deck, creating a cyclone effect that floats the grass clippings. Meanwhile, the blades dice them to a light, spreadable consistency.

closing side-discharge opening on a mulching lawn mower
Make sure that the side-discharge chute is closed before you start mulching.

Therefore, many out-of-the-box mulching lawn mowers have neither side- nor back-discharge outlets. That’s because, as we already mentioned, you want to keep the grass circulating in the deck.

That said, if you’re using a mower capable of cutting, bagging, or mulching, make sure you close the discharge chutes.

The Benefits of Using a Mulching Lawn Mower

Discover the positive impact mulching lawn mowers can have by learning about the benefits they provide you, your lawn, and the environment.

Benefits for You

You might be wondering if you should mulch or bag your grass clippings. That’s often a matter of personal preference, and each method has its advantages. 

One of the most significant benefits of mulching lawn mowers is how much time they save. Interestingly, they can reduce your mowing times by up to 50%. After all, you no longer have to empty your clipping bag or rake up strewn clumps.

For Your Lawn

what is a mulching lawn mower and how it can help simplify yard work

Mulching lawn mowers return nutrients like nitrogen to your grass, which keeps them lush and green. The grass clippings also help keep your lawn moist, reducing your water needs and protecting your lawn in extreme heat.

Mulching mowers are also very useful in autumn, as they grind up leaves just like they do grass. This will make your fall lawn maintenance a breeze compared to what it was when you had to rake.

Nutrient Recycling

When you fertilize your lawn, it uses the nutrients from the fertilizer to grow nice and green. Many of the nutrients end up in the blades of grass. When you cut your grass and bag the clippings, it’s like removing fertilizer from your lawn.

Instead of taking it away, a mulching lawn mower chops the grass up and returns the nutrients to the soil, where they can be absorbed by the grass roots again. Each year, people spend hundreds of dollars fertilizing their lawns, and this process of nutrient recycling saves them money. 

Moisture Retention

Mulching your grass helps conserve water and keeps your lawn cool, making it more drought and heat-tolerant. Once cut, the clippings quickly dry and break down easily, returning the nutrients to the soil and helping to prevent your lawn from drying out

Depending on the type of grass, the clippings are about 75 to 85% water. Cutting your grass with a mulching lawn mower allows your lawn to retain that moisture.

For the Environment

Mulching lawn mowers not only make it easier to mow and care for your lawn, but they are also better for the environment.

Reduction of Yard Waste

regular mowers leave behind clumps of grass
Without a mulching mower, you leave behind clippings and create unnecessary waste by bagging.

On average, lawns produce about 1,500 pounds of grass clippings per year. While most of this is water, it must still be collected, bagged, and disposed of properly. 

Keeping grass clippings out of landfills is one of the best ways to help the environment. Even if you pay a flat rate for garbage disposal that includes yard trimmings, keeping grass clippings out of the waste stream will help reduce the overall disposal costs.

Decreased Need for Fertilizers

In the United States, about 90 million pounds of fertilizers are used on lawns each year. Unfortunately, about 50% of these fertilizers end up in nearby water sources due to improper application and overwatering. 

Still, your lawn needs fertilizer to be thick and healthy. You can help the environment and save money on fertilizers and lawn care costs by using a mulching lawn mower that recycles the nutrients back into the soil.

Choosing the Right Mulching Lawn Mower

Explore popular brands of mulching lawn mowers and find out what to look for when purchasing one. 

Considerations When Purchasing

Finding the best mulching lawn mower for your yard can be challenging. There are several types of mulching lawn mowers, available in different models, including riding lawn mowers, push mowers, and self-propelled mowers. 

You can also choose the fuel type, as you can find a host of gas or battery-powered mowers.

Here are the main factors to consider when purchasing a mulching lawn mower. 

Yard Size

mulching riding mowers
Riding mowers are probably the best option if your lawn is more than an acre.

The size of your yard is an important consideration when choosing any type of lawn mower. Most professionals recommend having a ½ to ¾ acre lawn before recommending a riding lawn mower. Large yards are also much easier to mow with larger mowing decks. 


Riding mowers work best on flat terrain. Using a riding lawn mower can be dangerous on sloped land. If this describes your yard, you may need to work on foot.

In that case, one option is a push model. However, we suggest you spend a bit more and get a lot from the best self-propelled mower for your yard.

Popular Brands and Models

All the best lawn mower brands carry mulching models. Discover the most popular brands and models to help you find the best one for your lawn.

Toro Self-Propelled Gas Lawn Mower

toro recycler self propelled mower

No doubt, the folks at Toro know their stuff when it comes to mowers, both residential and commercial. As a matter of fact, we named the Toro Recycler the highest-value lawn mower on our Best Self-Propelled Mower Reviews list.

In particular, this model is a three-in-one tool, meaning it can mulch, bag, or discharge.

Ryobi Cordless Battery Walk Behind Self-Propelled Lawn Mower

Cordless 3-in-1 Ryobi self-propelled mulching lawn Mower

The Cordless 3-in-1 Ryobi Self-propelled Mower is an excellent American-made model for many homeowners. You can switch between bagging, mulching, and side discharge mowing, and you never have to worry about dealing with messy fuels or checking the engine oil.

This tool comes with two 6.0 Ah batteries and provides 70 minutes of run time. Ideally, it can handle any yard size up to an acre.

Using Your Mulching Lawn Mower Effectively

Using a mulching mower is mostly just like using any other type of lawn mower. However, to maximize its effectiveness, use these tips for the best results.

Best Practices for Mowing

Mulching lawn mowers work best when your lawn is dry and not too tall. Don’t use the mulching function on your mower if you’re cutting wet grass or if your grass is too long.

Mowing Height

Grasses grow best when they are mowed at specific heights, usually between 2 and 3 inches. The best mowing height is about 3.5 to 4 inches. If it gets any longer than that, the mulching function won’t cut the grass into small enough pieces. 

Mowing Frequency

How often you need to mow your grass depends on several factors, including the time of year, the type of grass you’re growing, how you use fertilizer, and when and how much you water.

You may need to mow more frequently if you plan to mulch your grass clippings. On the upside, mulching your grass is faster than bagging or raking the clippings, and your lawn will always look neat and tidy.

Maintenance Tips

Keep the blades sharpened and regularly clean and maintain your mulching lawn mower and its deck so they perform smoothly and reliably.

Blade Sharpening

how to sharpen mower blades

Sharp mower blades are essential, but they are even more critical for mulching lawn mowers. Keep your blades sharpened using an electric grinder like the Oregon Economy Blade Sharpener or other specialized equipment such as the EMBSW Mower Blade Sharpening System


Cleaning your lawn mower after every use while the grass clippings are still moist makes it easier to keep it clean. Once the grass clippings dry, you’ll have a hard time removing them.

Some mowers have a garden hose attachment. But if you’re using an electric model, use a damp cloth to wipe it clean so you don’t void the warranty.

FAQs About Mulching Lawn Mowers

What is the difference between a mulching mower and a regular mower?

Mulching lawn mowers are designed to create a circular airstream that pulls the grass up while you mow, making it easier to get a clean cut. Then, the mower blades have several cutting edges at different heights that chop the clippings into tiny pieces. Conversely, regular lawn mowers just cut the grass and expel the clippings.

Can you use a mulching mower on tall grass?

Using a mulching lawn mower on tall grass is hard on the mower. It won’t work as designed because it’s harder to chop all the grass clippings when they are too long.

Is mulching better than bagging?

In many ways, mulching is preferable to bagging your grass clippings. However, there are times when bagging is the better method. For example, if you have to mow a wet lawn, bagging is better than mulching.

Does mulching lawns encourage pests?

Mulching will help improve the health of your soil, which in turn improves the health of your grass. However, healthy lawns have a lot of insect activity, and you may notice more worms and insects, including centipedes, mealy bugs, ants, and spiders, which could lead to infestations.  

What type of lawns benefit the most from a mulching mower?

All types of lawn grass are heavy feeders, and they require a lot of nitrogen to stay healthy and green, so they all benefit from mulching mowers. Bermudagrass is among those species that benefit the most because the tiny clippings help keep your yard lush and cool in the summer.

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