How Do Mulching Mowers Work?

Trying to decide whether a mulching mower is worth your money and want to know how it works?


Here, we’ve shared everything you should know about mulching mowers, including how they work, their pros and cons, and how they compare to conventional mowers with a grass collector.

✅Key Takeaways:

  • Mulching lawnmowers are wheeled mowers with special mulching blades that distribute cut grass back on the lawn as you mow.

  • These mowers work by cutting grass clippings into smaller pieces and feeding them evenly onto the soil, where they quickly decompose.

  • Mulching lawnmowers are time- and labour-saving and help to improve lawn health naturally, but mowers with a mulching blade are more expensive than conventional mowers, and you’ll need to be prepared to mow your lawn more frequently.

Table of Contents

❓ How Does A Mulching Mower Work? Quick Overview

A mulching mower works by cutting grass into smaller clippings, then feeding these clippings onto your lawn rather than propelling them into a grass collection box or bag. The mower is operated like any other conventional wheeled mower – the only difference is that you won’t need to empty the grass collector.

🤔 What Is A Mulching Lawn Mower?

A mulching lawn mower is a wheeled mower with a mulching kit or blade.


Mulching mowers are specifically designed to cut grass into fine pieces and distribute them back onto the lawn. Rather than collecting and bagging the grass, a mulching lawn mower uses a special mulching blade to chop the grass up small. These small clippings are called mulch.


You can find several different types of mulching mowers, including petrol-powered mowers, corded electric mowers, and cordless battery-powered mowers. Check out our best mulching mowers guide here.


Not all lawn mowers have a mulching attachment or blade, so make sure to check for this feature if you want to mulch your grass. Rear or side discharge is not the same as mulching – this simply ejects normal grass clippings onto your lawn, and the cuttings are too large to quickly decompose and will end up clogging your soil and emitting a bad smell.

  • Brand: GardenTek
  • Price: £

  • Power source: Corded electric

  • Cutting width: 33cm

  • Cut height range: 20-60mm

  • Weight: 9 kilograms

  • Grass box capacity: 30 litres

  • Dimensions (DxWxH): 101cm x 35cm x 115cm

  • Power: 1,200 W

♻️ How A Mulching Lawn Mower Works

Mulching mowers typically have a unique cutting deck and blade design that allows them to cut grass up small.


The cutting deck usually has a higher dome shape, which allows the grass clippings to be repeatedly cut and circulated inside the deck, and the blades have additional cutting edges or serrations to further break down the grass into finer pieces.


The mulch that’s produced by a mulching lawnmower is dispersed evenly across the lawn. This mulch layer is sparse and fine enough to decompose naturally without needing to be raked or swept away after you’ve finished mowing. In fact, mulch helps to support a healthy lawn, acting as a natural fertiliser and returning nutrients, moisture, and organic matter back to the soil.


Mulching mowers usually have a function that allows you to switch between mulching mode and regular grass collection or side/rear discharge mode. That means you have options if the conditions aren’t suitable for mulching (for instance, if your grass is too long or you’re mowing in damp conditions).


To get the best results from your mulching lawnmower, there are a few recommended operational practices:

  • Mow the grass regularly to avoid your grass growing too long, which will mean that too much mulch ends up back on your lawn, potentially killing the grass underneath.

  • Make sure to properly maintain the mulching blade and adjust the mowing height according to grass growth.

  • Don’t use a mulching lawnmower when the grass is wet. You’ll end up with clumps of grass over your lawn, which will smother the grass underneath.

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🏁 How Do You Start A Mulching Mower?

You start a mulching mower how you’d normally start a conventional lawn mower.


That could be simply plugging the mower in and pressing the power button, or going through the motions of starting a petrol mower. It depends on the type of mulching mower you own.


The only difference is that during setup, you’ll need to insert the mulching plug or blade into the mower deck to activate the mower’s mulching mode.


We’ve shared how to do this in the section below.

law, mower, mulching, setting, adjuster,

🧐 How To Attach A Mulching Kit To A Lawn Mower

Different lawn mower manufacturers have different instructions for attaching their mulching kits to their mowers.


Your user manual should have specific instructions on how to attach a mulching plug to your mower. But if you just want a general idea of how to install a mulching plug in a petrol lawn mower, here’s the general step-by-step process:

  1. Remove the grass box (if you have assembled this already).

  2. Lift up the grass box deflector.

  3. Slide the mulching attachment into the back of the mower and press it down until it clicks in place.

  4. Shut the grass box deflector.

More of a visual learner? Check out the video below for a practical demonstration of attaching a mulching kit to a petrol mower.

📑 How To Use A Mulching Mower: Step-By-Step

Using a mulching lawnmower is just like using any other lawnmower. Here’s a quick step-by-step on how to use a mower with a mulching blade or kit:

  1. Attach the mulch plug. Follow the instructions in your user manual to insert the mulch attachment in the mowing deck.

  2. Switch the mower on. If you have an electric or battery mower, press the “start” button and keep hold of the safety switch. If you have a petrol mower, prime the engine and pull the starter cord.

  3. Mow your lawn. You should notice the grass cuttings dispersing as mulch onto your lawn as you mow.

  4. Clean the mower. Switch off the mower and carefully clean the mower blade and deck before putting it back into storage.

🤼 Mulching Mowers Vs Grass Collection

Mulching is quicker and less physically demanding than grass collection, but it’s not suitable for all situations.


Using a mulching lawnmower means you don’t have to stop to empty collected grass on your compost pile or in your garden waste bin.


The mulch returns valuable nutrients to the soil, helping your grass to grow more healthily than if you followed the conventional grass-cutting-and-collection procedure.


However, not everyone wants to see grass clippings scattered on their lawn, and you might prefer to spend less money on a regular mower that can be used to cut grass of all heights and won’t increase your mowing frequency.

👍👎 Pros & Cons Of Mulching Mowers

Let’s take a quick look at the pros and cons of mulching mowers:


👍 Mulching Mower Pros

🚑 Improved Lawn Health

Mulching mowers promote a healthier lawn by returning the finely chopped grass clippings to the soil as you mow. These clippings act as a natural fertiliser, providing nutrients that the grass needs to grow healthily.


⏰ Time And Labour Saving

Mowing with a mulching lawn mower will help you cut down on the time and labour involved in the job. You won’t have to pause to periodically empty lawn clippings into your garden waste bin or onto your compost heap, and you don’t need to rake or sweep the clippings off your grass once you’ve finished.


🔋 Several Power Types To Choose From

There are different mulching mower power types, including electric corded mulching lawn mowers, petrol mulching mowers, and battery-powered mulching lawn mowers, so you can choose the right power type for your lawn size and your personal preferences.


😇 Environmental Benefits

Using a mulching lawn mower is a sustainable lawn care practice that’s kinder to the environment than regular mowing with grass collection. You can recycle your grass clippings on-site, reducing the waste that ends up in landfills, and fertilising your lawn with natural organic matter should eliminate your need to use synthetic chemical fertilisers.

multched, lawn, cutting, grass,

👎 Mulching Mower Cons

💰 Mulching Feature Costs Extra

You’ll spend around 10-20% more on a mower with mulching blades than you would on a conventional mower with no mulching kit. The extra upfront cost is worth it if you plan to use the mulching mower blade every time you mow (or at least as often as you can), but you’ll have to budget more money for the purchase.


🗓 Requires Regular Mowing

Using a mulching lawnmower also means mowing more frequently. You can’t mow long grass with a mulching mower because if there’s too much mulch produced, it’ll build up on your lawn, being unable to decompose quickly enough, and increase the risk of thatch buildup.


💦 Can’t Mulch Wet Grass

Ideally, you shouldn’t mow your lawn when the grass is wet anyway, but if you have no choice but to get your mower out, you won’t be able to use the mulching function. The wet grass clippings will clump together and won’t distribute evenly across your lawn, leaving piles of grass that will smother the lawn underneath.

Pros & Cons of Mulching Mowers

✔️ Pros of Mulching Mowers

Improved Lawn Health Promotes healthier lawn by returning clippings to soil
Time and Labor Saving Reduces time and labor in lawn maintenance
Several Power Types to Choose From Options: electric, petrol, battery-powered mowers
Environmental Benefits Reduces waste and synthetic fertilizer use

❌ Cons of Mulching Mowers

Mulching Feature Costs Extra Higher upfront cost compared to conventional mowers
Requires Regular Mowing Requires more frequent mowing
Can't Mulch Wet Grass Not suitable for wet grass

🛠 How To Maintain A Mulching Mower’s Performance

There are a few specific maintenance tasks that you will need to carry out depending on your lawn mower type, including changing the oil, topping up the fuel, charging any batteries, and tightening screws, nuts, and bolts.


Two key maintenance jobs to sustain the best mulching performance from your lawn mower are:

  • Sharpen the mower blade once or twice per season, or after every 20-25 hours of use.

  • Clean the mower deck after every use.

These jobs will ensure your mower can effectively mulch grass cuttings throughout the year and prevent the spread of grass diseases, which could quickly get out of hand when you’re mulching the grass back into the lawn.

💸 Are Mulching Mowers Worth It?

Most people can see the appeal of a mulching lawnmower because it reduces grass cutting time and minimizes the effort that goes into mowing a lawn.


Mulching lawnmowers are worth it for you if you just want to mow your lawn as quickly as possible, you don’t have a convenient location for your grass clippings (i.e. a garden waste bin or a compost pile), or you’re focusing on caring for your lawn organically.


However, these mowers probably aren’t worth it for you if you hate the look of decomposing grass on your lawn, you don’t want to upgrade your regular mower to a mulching model, or you often let your grass grow long and wouldn’t get desirable or optimal mulching results.


Regardless of the mower you choose, make sure the manufacturer is reputable and there are plenty of positive reviews from customers and industry experts alike.