What is a Mulch Lawn Mower? A Professional Guide

Self-mulching lawn mowers are a type of mower that make use of freshly-cut grass clippings and distribute them across the lawn as compost. With blades that create much smaller pieces of grass and organic matter, mulch mowers allow you to provide lawn care while cutting the grass.

There are ride-on and walk-behind varieties, as well as mulching kits for existing mowers. Examples of quality mulch lawn mowers of each type from our range include the following:

• Snapper SPX275 48″ Rear-Discharge Ride-On
• Honda HRS 536 VK 21″ Variable Speed Mulching Mower

We provide competitive pricing and fast delivery on mulch mowers, so we understand their features and benefits very well. The following are some questions and answers that will serve as a good overview and guide on how a mulch lawn mower works and what mulching involves.

How Does a Mulching Lawn Mower Work?

When you mow the lawn with a conventional mower you will be collecting the grass clippings, other organic material and thatch buildup in a removable bag, which you then have to empty. However, a mulching lawn mower discharges the clippings to the side or rear of the mower.

The mulch blades are capable of cutting the grass into very fine pieces. But, instead of going to a bag attached to the mower, they are then fed through to a discharge chute, which lets you smother the grass with an even compost pile that promotes the health and look of the lawn.

If you are using a mulching kit, you simply keep the discharge chute blocked using the mulching plug – the mulching blades will blow back the particles into the sward (which is the upper layer of the soil) and allow them to penetrate deeper into the surfaces of the lawn.

Are Mulching Mowers Food For the Lawn?

Yes. Mulch in general makes an excellent plant food for the lawn. Spreading mulch allows the remaining grass and soil to gather nutrients and can help to fertilise the areas where the mulch is spread. The act of mulching spurs microbial activity and is a clever way to make use of what would otherwise be considered waste. In a regular compost heap, mulching is often done manually with a spade or digging fork by turning over the layers of composting grass and leaves.

What is a Mulching Plug or a Mulching Kit?

A mulching kit consists of a set of blades and a mulching plug that you use to convert an existing tractor or mower into a mulching mower. The mulching blades are special grass cutting blades that are designed to cut the grass into smaller pieces and the mulching plug is used to block the mower’s discharge chute to the bag and instead blow it across the lawn. 

Many people buy mulching kits to create their mulches from grass, leaves and other garden waste. The key advantage to using a mulching kit, as opposed to a purpose-built mulching lawn mower, is the ability to take it off or put it back on as required. Mulching kits work best for grass that is not too long, so the grass can be evenly blown back into the lawn.

What Does a Mulching Lawn Mower Do?

A mulching lawn mower simply mulches as you mow, which means you can spread fertilising organic matter across the lawn. Mulching lawn mowers have the following additional benefits:

• Save time and money: Mowing, collecting grass in a bag and disposing of it is extremely labour intensive. A mulch lawn mower reduces the time spent mowing and eliminates the need for throwing things away, while also producing free fertiliser.
• Eco-friendly: You avoid using expensive, sometimes harmful, fertilisers with a mulch lawn mower. By using the free food for the grass and soil that comes from your grass clippings you have a low-impact form of mowing.
• Healthy grass appearance: Many golf courses use commercial mulch lawn mowers to keep their grass looking greener, brighter and healthier. You can get this benefit at home and in all sorts of other commercial environments or on large public estates too
• Fewer weeds: Because mulching mowers are used more frequently and promote better grass health they reduce the number of weeds that poke through any of the patchy areas of unhealthy grass.

There are no real drawbacks to the process of mulching itself, but it requires a lot of consistency in your routine and the initial investment for a mulching mower is typically quite a bit higher.

When to Use a Mulching Lawn Mower

Aside from the differences in where the grass chute leads, to the side or rear of the mower or directly into the sward, the principles of your ride-on or walk-behind variety are the same. If you are using mulching kits, you need to insert the mulching plug and fit the blades before mowing.

There are a few tips for better results when using a mulch lawn mower, such as the following:

• Avoid wet grass or leaves, this means the blades will not be able to cut the grass so finely
• Do not use a mulching mower on very long grass, as it will not mulch as well and can even block the blades in some cases
• Remove weeds very carefully before mulching, or you will spread their seeds around and this can result in new weeds growing all over the sward

You should also aim to cut a lawn of any size at least once a week with a mulching mower, as longer grass can lead to weeds developing and make it much harder for the mechanism to work. The frequency might need to be increased depending on the stage of the growing season.