What Are "Mulching" Mowers? Do They Really Provide Mulch?

Fertilize the Lawn While Simultaneously Saving Yourself Work

Lawn mower and grass
You'll need a bag attachment if you're mowing with a regular mower. The bag catches the grass clippings. With a mulching mower, a bag is unnecessary. Sean Hobson/Flickr/CC BY 2.0

Someone new to maintaining lawns once asked, "What are 'mulching' mowers? Do they really provide mulch?" Let's explore this issue in some detail, because there are some important lessons in lawn care here for homeowners with no experience in cutting grass.

Why You Might Want to Buy a Mulching Mower

Mulching mowers are useful machines in caring for the lawn, but their purpose is not to provide mulch.

The reader's confusion is understandable, though. Usually, when we hear the term, "mulching," we think of spreading mulch around with a shovel. Mulch is a multi-functional material, perhaps most valued for its ability to suppress weed growth. Tree bark is commonly used for this purpose.

But "mulching mowers" give the term a new twist. "Mulching" in this case is a bit of a misnomer. These machines do not make mulch; if anything, the product they leave behind is more of a compost or a fertilizer. This source of organic matter breaks down and supplies your grass with nutrients. Using this type of lawn mower is one step you can take to keep your grass fed while avoiding the application of chemical fertilizers.

The alternative to a mulching mower is a lawn mower that comes with a bag attachment to collect grass clippings. If you opt for the latter, you should deposit the clippings into a compost pile, so as to acquire free compost for the garden and avoid wasting community landfill space.

The grass clippings left behind by a mulching mower essentially function as a lawn fertilizer, as if you were applying compost to the lawn. For this reason, it makes more sense for most urban and suburban homeowners to use a mulching mower, rather than bagging their grass clippings and dumping them in the compost pile.

Essentially, mulching mowers eliminate the "middle-man," namely, the compost pile, instead providing you with compost directly. This means less work for you.

Mulching mowers are designed so as to leave behind finely shredded grass clippings. Such clippings can be left on the lawn with impunity. By contrast, because lawn mowers without mulching capabilities produce clippings that are bulkier and readily mat together, their clippings need to be removed from the lawn, so that the grass does not suffocate under them. This is the reason why people using neither a mulching mower nor a machine with a bag attachment have to rake up their lawn clippings. While this third alternative is surely a possibility (my dad always made me rake up the grass clippings after he mowed the grass when I was a child), you can see why, nevertheless, it would also be the most labor intensive approach. But when folks cut the grass with reel mowers back in the old days, there was not much choice.