What is a Mulching Lawn Mower and Should You Buy One?

Have you considered buying a mulching lawn mower but are not sure if it’s the right choice for your lawn?

In this guide, I discuss the benefits and downsides of using a mulching lawn mower to help you make an informed decision with your lawn mower purchase.

What does a mulching lawn mower do?

Essentially, a mulching lawn mower doesn’t have a catcher that collects the lawn clippings so you can add them to your compost. Instead, a mulching lawn mower chops the clippings up and then deposits them all over the lawn as you mow.

The way it works is that these mowers have multiple individual blades. These blades first cut the grass as you’re mowing and then the clippings are cut up continuously until they are mulched into very small pieces. 

The tiny pieces of mulched grass are then deposited back onto the lawn as you move over it with your mulching mower.

What are the benefits of a mulching lawn mower?

One of the biggest benefits of using a mulching mower is that the mulched clippings are distributed back over the lawn so as they break down, they add valuable nutrients back into the soil.

Because lawn clippings generally contain around 90% water, when the clippings are cut up finely, they tend to dry much faster. This also allows them to break down much quicker to replenish the nutrients in the soil.

Ultimately, this means that you don’t have to use a lot of fertiliser to feed your lawn and keep it green. This not only saves you money but time as well.

Additionally, you don’t have to stop often while you’re mowing to empty the catcher and dispose of the grass clippings.

Using your grass clippings to fertilise your lawn is also better for the environment because it stops you from having to apply chemical fertiliser that may leach into surrounding waterways.

How is the design of a mulching mower different from that of a regular mower?

Lawn Mower 1 | Lawn care

There are major design differences between a mulching mower and a regular lawn mower that has a catcher. Primarily, there are differences in the mower blades and also the mower deck.

In a mulching lawn mower, the blades are curved rather than straight. This allows the blades to direct the lawn clippings back into the deck so that they can be cut again and again until they are fine.

Once the clippings are finely cut, the blades then force the clippings back out onto the lawn.

So, mulching lawn mower blades have three functions:

  • To cut the grass
  • To chop the clippings up finely into mulch
  • And finally, to force the fine clippings back onto the lawn

The deck on a mulching lawn mower is also different from that of a regular mower. Generally, it’s a little wider so that there’s enough room for the clippings to continue to circulate in order for them to be cut up finely.

You’ll also find that the deck on a mulching mower is a little higher. This is to allow greater airflow which helps to keep the clippings circulating. 

Advantages and disadvantages of using a mulching lawn mower

In order for you to decide whether a mulching lawn mower is a perfect choice for your lawn, here is a list of the pros and cons.


  • Returns valuable nutrients back into the soil
  • Saves you money on fertiliser costs
  • Saves you time because you don’t have to apply fertiliser or empty the catcher
  • More environmentally friendly


  • The deck can get clogged up if the grass is very long
  • Continually adding clippings to the lawn can increase thatch
  • If the grass is wet, it can cause the mower to deposit clumps on the lawn

How to overcome the downsides of a mulching mower

The disadvantages of mulching lawn mowers can easily be overcome by following good mowing practices. Here are some tips.

How to prevent your mulching mower from getting clogged up

The first thing you want to do is check the deck and give it a good clean. Use a scraper to clean all the dried clippings off from around the deck. A clean deck means that the clippings can move around freely and then get deposited back onto the lawn.

You might also find that if the grass is too long, there are just too many clippings for your mower to handle efficiently. For this reason, many mulching lawn mowers also have the option of a side-discharge chute. This directs the excess clippings back onto the lawn instead of mulching them.

Therefore, if you don’t mow your lawn frequently enough, make sure that you invest in a mulching mower with a side-discharge chute. The only downside to this is that you’ll have to rake up the clipping after you’ve finished mowing.

How to prevent thatch buildup

The best way to prevent thatch buildup is to mow your lawn often and on a regular basis. If you do this, you won’t have a problem with thatch.

How to prevent your mower from depositing clumps of grass

The solution to this one is quite simple. Don’t mow the grass while it’s wet. Wait for the grass to dry in between periods of rain and you shouldn’t have a problem with clumps being left on your lawn.


Do you have to mow slower when mulching?

Yes, you should move slower over your lawn when you use a mulching mower. This will give the mower enough time to effectively chop up the clippings.

What is the main downside to mulching your lawn?

The main downside of mulching your lawn is that you have to mow on a regular basis to get the best benefits. You also have to wait for the grass to dry out before you mow and you have to regularly maintain the mower deck to ensure that it’s clean.

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Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.


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