Reasons You Should Shred Leaves for Compost and Mulch

orange and red fall leaves being raked up
David Beaulieu

You may have heard of the practice of shredding leaves prior to trashing them, putting them in the compost, or using them as mulch. Is it just to make it easier to dispose of the leaves, since, once shredded, the load would be more compact? Or is there some other benefit? Here are the reasons to shred leaves before disposing of them or using the.

Shredded Leaves Make Great Compost and Mulch

After raking leaves in the fall, you take the additional step of shredding them with a leaf shredder, lawn mower, or another device. Shredding leaves is a good idea regardless of whether your main interest is in disposing of them, producing leaf mulch, or producing compost.

Most people who go through the trouble of shredding leaves do so for the purpose of using them in the landscape, rather than disposing of them. This is smart because leaves are biodegradable and a wonderful source of organic matter with which to enrich your garden beds and/or suppress weeds. Why pay for compost and mulch when you can make your own?

They Take Up Less Space

If you do decide to dispose of the leaves that you rake up in fall, shredding them first means there will be fewer air spaces when you stuff them into the disposal bags. Having fewer air spaces means, in turn, being able to cram more leaves into each bag. The result is that you will use fewer bags.

Shredded Leaves Make Better Mulch, Quicker Compost

The best mulches are porous enough to permit the penetration of air and water to the soil, thus promoting plant health. While not a consideration in the winter for vegetable gardens and annual beds (in case you need to mulch these areas in winter just to prevent erosion), this becomes a factor if the mulch is to be used once spring rolls around again. Thus the reason for shredding leaves for use as mulch: An application of unshredded leaves would mat down, forming an impervious layer that would not "breathe" and that water would run off. This state of affairs would not be good for the plants in the garden beds in question.

If you garden organically, you will probably applaud the fact that leaf mulch will not remain leaf mulch forever. Leaf mulch is just compost waiting to happen. That is right: as the leaf matter decomposes, valuable nutrients will be released into the soil and made available to your plants. While you lose your mulch as a result of this process, you more than make up for the loss by gaining compost. You can hasten this natural process by shredding leaves before applying them as a mulch.

Fun Fact

By composting, you help to reduce organic waste in landfills. It also helps lock carbon into the soil, which reduces carbon dioxide in the atmosphere.

It Works Better For Compost

What has just been described is compost production that does not involve a structure set aside to house decomposing matter (termed a "compost bin"). That is, you set out primarily to make mulch, but you end up with compost as a bonus. Of course, some gardeners skip the mulch phase altogether and just place the shredded leaves directly into a compost bin, for the purpose of breaking them down into organic matter as quickly as possible. Here, too, shredded leaves work better. The reason? The typical compost pile works best when aerobic organisms are allowed to flourish. As that word implies, it is essential that the pile breathe. Unshredded leaves would mat down and discourage the aerobic organisms you need for efficient decomposition.

How to Shred Leaves

Some people use a machine called a "leaf shredder" to do their shredding. Some types vacuum up the leaves, shred them, then gather them into a bag. But this convenience will cost you.

Most wood chippers also shred leaves, though you certainly don't need one, and they usually aren't very good at dealing with sticks. The wood chipper is typically more of a heavy-duty device, and you will pay for that extra quality. If you do not need to chip the wood, you generally can get by more inexpensively by just sticking with your lawnmower.

Just run your lawn mower over your leaves to shred them. Not only is this a cheaper alternative (since you already own the mower), but, if you have a bag on your mower that collects grass clippings, you do not sacrifice any convenience.