How to Mulch
Think you know all about this basic garden technique? Learn tips to get the most out of mulching.
How much do you know about mulch?
Mulching sounds simple, and gardeners may wonder why we need an entire book about it. After all, it’s just means putting a layer of chopped leaves or other materials around the plants in your garden, right?
The answer is yes—and no. Mulching is easy, but there’s more to it than you may suspect, according to Jennifer Kujawski and the late Stu Campbell, authors of How to Mulch: Save Water, Feed the Soil, and Suppress Weeds.
You probably already know mulching helps hold moisture in the soil, but did you realize some studies have shown it can retain up to 50 percent? That has big implications. It means we're doing our part for the environment when we mulch by helping conserve a precious natural resource and we're getting the added benefit of saving money on our water bills.
Mulching also helps control weeds, which is not a surprise. But do you know how to choose the right material? One of my earliest mistakes as a young, inexperienced gardener was to mulch with hay loaded with weed seeds. I pulled weeds until frost—for several years.
If you’re relatively new to gardening, you also may overlook how mulch can encourage a population of earthworms in your garden. As it absorbs rainfall, mulch helps prevent the soil underneath from becoming compacted and crusted. That means it’s easier for these beneficial worms to move through the earth, creating channels for water and air and depositing nutrient-rich castings (waste products).
You’ll also hear about the dark side of mulching, so to speak. Fresh mulch can rob your plants of nitrogen as it decomposes, so you may need to add cottonseed meal or another source of nitrogen to compensate. The authors also warn about using plastic mulch, which may cause problems when sufficient rainfall and oxygen can’t reach plant roots.
Campbell and Kujawski explain how to banish slugs, snails and other unwanted pests from the mulch around your plants (try adding crushed eggshells or sharp sand) and how to deter rodents that nest in mulch (shield your plants with wire or quarter-inch hardware cloth).
The authors also discuss a variety of materials you can use for mulch, such as evergreen boughs (had you thought of sawing up your cut Christmas tree when the holidays are over to use around your shrubbery?), biodegradable black paper (available from the waste collection sites of some municipalities) and synthetic geotextiles (also good for controlling erosion, especially around construction).
Different mulches are categorized by whether they’re best used for function or aesthetics. You’ll also pick up tips on using mulch in new ways. “Flakes” or “books” of straw can be peeled away from bales and placed between rows to walk on, for example. And you'll learn not to pile mulch around your trees in volcano shaped piles; it invites rot and gives hungry, bark-chewing creatures a dark, moist place to hide.
Mulching guidelines are provided for some specific plants. Diagrams show how to mound soil or build wire cages filled with compost to protect rose bushes in winter. Other sketches show mulching techniques to extend your asparagus harvest, help “blanch” celery and grow potatoes without digging into the soil. You’ll also find recommendations for how much mulch to use around some commonly grown fruit trees and berries.
At less than 100 pages, How to Mulch is part of the Storey Basics series, and it’s a fine choice for new and beginner gardeners. Experienced green thumbs can find good advice here, too, and may pick up some helpful tips along the way.