Garden Mulch Types

How to choose them and how to use them

Newspaper (image) can smother your grass. Apply mulch to weigh it down.
David Beaulieu

Garden mulches are your first line of defense against weeds. Mulching is one of the most beneficial practices you can adapt to maintain the grounds around your home. Below is a primer on garden mulch types, including what kinds of mulch you can use, varieties, when and how to apply mulch—and even what gardeners mean by "living mulches."

Garden Mulch vs. Compost

Mulch and compost are not synonymous, nor do they serve the same function. Compost should be worked into the soil to make it more fertile; mulch, by contrast, is spread atop the soil to protect it from the elements and to suppress weeds. While organic mulches eventually decompose, thereby becoming compost, their function as long as they serve as mulch is distinct from that of compost.

Using Leaves as Mulch

You can spread leaves you have raked in vegetable gardens and annual flower beds, but always shred the leaves first, before using them as mulch, and prepare your garden before adding any kind of mulch. Hold off on using leaf mulch in perennial flower beds until the ground over your garden plants has frozen, as a premature application could smother your flowers. 

Rototill Before Mulching

Use a small rototiller—you can rent them at most hardware stores—to make your job easier. Rototill in the fall, but before you do, have your soil tested; you might find that the soil pH needs to be corrected. If your soil needs garden lime, this is the time to spread it on and use the rototiller to work it under. The benefits of lime are slow to manifest themselves, so don't wait until spring. Rototilling the lime into the soil in fall will yield benefits in next year's garden.

Mulch in the Fall

Garden mulch applied in the fall keeps the severe weather conditions of winter from eroding your soil and robbing it of valuable nutrients. As an insulator, mulch works in two ways: It shields your plants' roots from some of the worst of winter's cold, sometimes making it possible for you to grow plants that are only borderline hardy for your region; and, by insulating the frozen soil from the sun's rays on that odd mild winter day, your plants will remain in their protective state of dormancy.

As a bonus, when the mulch decomposes, it will release valuable nutrients into your soil. Garden mulch also improves moisture retention in the soil, cutting down on your water bill in the summer. Finally, if you walk over a portion of your garden frequently, mulching it will reduce the chances of your developing compacted soil in those well-trodden spots.

Should You Use Newspaper?

Old newspapers are not safe for compost—especially if you are raising food crops, as opposed to ornamentals—because of the composition of their ink, which includes toxic ingredients such as cadmium, lead, and chromium. But most newspaper inks of the 21st century are soy-based and regarded as safe. To make sure, call the publishing headquarters of the newspaper in question and find out if they use a soy-based ink. If they do, the newspapers may be relatively safe for mulch and compost.

If you wish to be a real stickler about it, ask a separate question regarding their colored pages (if any), as the inks used for these pages may contain harmful ingredients. Or, to be on the safe side, simply keep the newspaper pages with colored ink out of the garden.

While you have the publisher on the telephone, ask how the paper is bleached. Traditionally, harmful chemicals were used in the bleaching process. More commonly today, hydrogen peroxide—a safe alternative—is used to bleach newspapers. Before using newspaper in the garden, check that the paper in question has not been bleached with harmful chemicals.

Using Newspaper as Mulch

A material does not need to be fertile -- that is, contain a lot of nutrients—to do a good job of suppressing unwanted plants. Newspaper is particularly useful as a mulch when you are trying to open up a new planting bed by killing grass and/or weeds across a large area. Because it comes in sheets, it is a ready-made barrier and easy to work with. You can quickly cover wide swaths of the earth in newspaper. 

When using newspapers as a more conventional mulch—such as around plants—lay them just two or three sheets thick and poke holes through them in such a way that water can penetrate to the plants' roots. Wetting the papers will help hold them down, as will spreading a natural mulch, such as straw, on top of them; this will also improve the appearance of your garden because newspapers used as mulch can be an eyesore.

To use your newspapers for compost, shred them first before adding them to the compost bin. The materials in a compost pile need to "breathe" to break down. To breathe, they need air, which means they should not be matted down. An unshredded newspaper has a strong tendency to mat down, so run newspaper through a shredder before tossing it into a compost bin.

Cover Crops—"Living Mulches"

If you need to mulch a large garden in fall, and you don't have enough leaf or newspaper mulch for the job, use cover crops—live plants that are sometimes called "living mulches." Cover crops are an alternative to mulching with bark, leaves or other conventional mulches to protect your soil for the winter. Cover crops are also sometimes referred to as "green manure crops." They derive the name from the fact that, once tilled into the garden, they fertilize the soil—as would manure.

Some gardeners choose to use cover crops in both their capacities: as "living mulches" for winter protection and as "green manure crops" that will be tilled under in spring. After tilling the cover crop under, apply a conventional mulch onto the garden to suppress weeds for the spring and summer.

Mulching Tips