What's A Mulching Lawn Mower?

23 August 2022


Mulching lawn mowers have long been a popular choice for gardeners keen to maintain and encourage a green, healthy lawn. The mulching process helps to improve the texture of the soil, conserve soil moisture, help to prevent the growth of weeds and help to reduce potential diseases to the grass. However, the UK climate isn’t suitable for mulching all year round, so it is important to understand what mulching is and how to choose a suitable mulching lawn mower for your gardening requirements.

What is mulching?

Mulch is a layer of material that is spread over the surface of the soil, designed to improve the fertility and health of the soil, enhancing the visual appeal of the lawn whilst also reducing the appearance of weeds. 

The process of mulching refers to the fine, double cutting of grass. These fine grass clippings are then dispersed and spread back over the lawn, rather than being collected in a separate grass bag to then be disposed off separately, as occurs with cylinder or rear discharge rotary lawnmowers. 

Mulching is most effective during drier periods, typically spring and summer in the UK. When decomposition is slow, typically at the beginning and end of the growing season, mulching is less effective and therefore it is recommended to remove the clippings from the lawn. 

Are mulching lawn mowers good for the lawn?

Mulching has many benefits, namely for the gardener, the lawn and the environment. 

For gardeners, mulching helps to cut down on the grass cutting time. This is primarily because you do not need to collect and dispose of the grass cuttings, as they are spread over the lawn. For large lawns, collecting and disposing of the grass cuttings can be a tiresome and time consuming task, even if you have a compost heap. 

Mulching lawn mowers have many benefits for your lawn, primarily as mulching helps lawns to conserve moisture as the mulch layer helps to reduce evaporation from the soil surface. Additionally, the mulch layer of grass itself is predominantly water. When this mulch layer starts to decompose, the clippings will return the moisture, nitrogen and nutrients to the soil beneath it.

The benefits of conserved moisture include but are not limited to:

  • Healthier lawns as a result of the grass roots receiving nutrients and greater moisture.
  • More visually appealing, greener grass.
  • Reduced need to water your lawn, saving time and precious water.
  • Helps to prevent the growth of weeds and reduces the risk of diseases to the grass.

As mulching helps to retain and conserve moisture within your soil, it is a near essential gardening tip for UK lawns, especially when many areas of the country are hit with hosepipe bans or water preservation notices. Additionally, many households do not have access to a compost heap or garden waste recycling bin, and therefore grass cuttings often end up in a non-recycling general waste bin in a black liner. Therefore, if the grass cuttings can be repurposed as mulch on the lawn, there can be significant environmental benefits compared to collecting and disposing of the cuttings. 

However, a layer of mulch can lead to detrimental effects for your lawn in wet periods such as the autumn or winter. An overly damp soil can lead to a weed problem, and will exacerbate an existing worm problem as the grass clipping mulch will prove popular for worms and in certain instances, even moles.  

There are situations where it is not recommended. These include:

  • If there is a fungus or disease in your lawn, do not mulch. This will only serve to spread the disease further around your grass.
  • Leaves and mulch do not necessarily combine to make a good combination. If there is a dominant leaf coverage, do not mulch the lawn as this can damage the grass. 
  • If your lawn has weeds that are going to seed, do not mulch, as this will help to redistribute the weed seeds.
Are Mulching Lawnmowers Good For The Lawn

Choosing a suitable mulching lawn mower

When purchasing a mower from a lawn mower shop like Horace Fuller, often you will have to weigh up the pros and cons of mulching, side discharge and bagging mowers. 

There are many similarities between the main types of lawn mower available. Namely, a stream of air is directed at the grass to ensure the grass is vertical while the lawn mower blade cuts.
Then, what happens to the cuttings is rather different. 

Side discharge mowers are designed to deposit the cut grass to the side, whilst bagging mowers collect the grass cuttings into an easily-detachable bag that can then be disposed of. Mulching mowers will direct the grass cuttings through the blades multiple times, before depositing the finely-chopped cuttings back onto the lawn. Mulching blades have curved edges and generally have a greater cutting surface area compared to standard blades.

Through the use of a mulching plug or mulching plate, even dedicated side-discharge garden tractors can be used for mulching with excellent results.

However, modern petrol rotary lawn mowers that offer mulching capabilities through the use of an attachment such as a mulching plug or plate are not as effective as a full-time dedicated mulching lawn mower, as in some instances the grass will not be cut using the double cut method. 

Many petrol lawn mowers available today offer up to ‘4 in 1’ capabilities, offering not only the ability to mulch, but also to collect, side discharge or rear discharge the grass. For gardeners seeking an excellent value for money and well rounded lawn mower, these are a great solution.

What is a lawn mower mulching plug?


Can any lawn mower be used for mulching?

Both ride-on mowers and push mowers can be used for mulching, although lawn mowers not initially designed for mulching will require a mulching conversion kit, which typically requires a plate (sometimes known as a mulching plug) and a new mulching blade. 

Do you need a specific mulching blade?

In theory, even a normal blade can be used for mulching if you are able to close the discharge chute or remove the bag. However, a normal blade will not return the same results as a specifically designed mulching blade as the grass cuttings will not be as fine, meaning the cuttings take longer to break down and release their nutrients, nitrogen and moisture into the soil. 

What is a mulching plug?

A mulching plug is a lawn mower attachment that is used to close the discharge opening of a side or rear discharge lawn mower, so that it can be used for mulching. 

Can I mow the lawn when it is wet?

Aside from any safety concerns, it isn’t recommended to mow the lawn when wet; especially when using a mulching lawn mower. This is because the wet grass will clump, and the blade will struggle to cut the grass cuttings as finely compared to a dry lawn.

We hope you have found our 'What's a mulching lawn mower' article interesting, and hopefully now know how and why they are in many cases a useful addition to homeowners gardens. 

If you are interested in any acquiring one of these machines yourself, take a look at some of our mulching lawn tractors here

As an official garden machinery supplier of various brand manufacturers, we also have a wide array of other products available.  

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