Adding mulch to your garden
Adding mulch to your garden is one of the best things you can do for healthy soil—here are 6 ways to do it right.
The best time-saving measure a gardener can take is adding mulch. From vegetable gardens to flower beds, mulched gardens are healthier, have fewer weeds, and are more drought-resistant than unmulched gardens. Done properly, it’ll allow you to spend less time watering, weeding, and fighting pest problems.
Organic and Inorganic mulch
First, when adding mulch, you will find two basic kinds of mulch: organic and inorganic. Organic mulches include formerly living material such as chopped leaves, straw, grass clippings, compost, wood chips, shredded bark, sawdust, pine needles, and even paper. Inorganic mulches include gravel, stones, black plastic, and geotextiles (landscape fabrics).
Both types discourage weeds, but organic mulches also improve the soil as they decompose. Inorganic mulches don’t break down and enrich the soil, but under certain circumstances they’re the mulch of choice. For example, black plastic warms the soil and radiates heat during the night, keeping heat-loving vegetables such as eggplant and cherry tomatoes cozy and vigorous.
There are two cardinal rules for using organic mulches to combat weeds. First, be sure to lay the mulch down on soil that is already weeded, and second, lay down a thick enough layer to discourage new weeds from coming up through it. It can take a 4- to 6-inch layer of mulch to completely discourage weeds, although a 2- to 3-inch layer is usually enough in shady spots where weeds aren’t as troublesome as they are in full sun. If you know that a garden bed is filled with weed seeds or bits of perennial weed roots, you can use a double-mulching technique to prevent a weed explosion. Set plants in place, water them well, then spread newspaper and top it with organic mulch.
Mulching your garden and how to get the best out of each mulching method
Spreading organic mulch saves labor and nurtures plants by preventing most weed seeds from germinating, and the few that do pop through the mulch will be easy to pull. Keeping the soil cool and moist in summer, organic mulch reduces the need to water. It also decomposes slowly, releasing nutrients into the soil. It encourages earthworm activity, improving soil tilth and nutrient content. Plus, it prevents alternate freezing and thawing of the soil in winter, which can heave plants from the soil.
Unfortunately, nothing is perfect. When using organic mulches it’s important to keep in mind that as low-nitrogen organic mulches such as wood chips and sawdust decay, nitrogen is temporarily depleted from the soil. Fertilize first with a high-nitrogen product such as blood meal or fish meal to boost soil nitrogen levels. An organic mulch retains moisture, which can slow soil warming; in spring, pull mulch away from perennials and bulbs for faster growth. A wet mulch piled against the stems of flowers and vegetables can cause them to rot; keep mulch about 1 inch away from crowns and stems. Mulch piled up against woody stems of shrubs and trees can cause them to rot and encourages rodents, such as voles and mice, to nest in the mulch. Keep deep mulch pulled back about 6 to 12 inches from trunks. In damp climates, organic mulches can harbor slugs and snails, which will munch on nearby plants; don’t spread mulch near slug-susceptible plants. Organic mulches are usually more or less acidic, depending on their content; mix some lime with the mulch beneath plants that prefer neutral or slightly alkaline soil.
Wood chips or shredded leaves
You can purchase bags of decorative wood chips or shredded bark from a local garden center to mulch your flower garden and shrub borders. A more inexpensive source of wood chips might be your tree-care company or the utility company. They may be willing to sell you a trunkload of chips at a nominal price. Many community yard waste collection sites offer chipped yard debris or composted grass clippings and fall leaves to residents for free (or for a small fee). Also, consider chipping your Christmas tree instead of tossing it to the curb.
If you have trees on your property, shredding the fallen leaves creates a nutrient-rich mulch for free. You can use a leaf-shredding machine, but you don’t really need a special machine to shred leaves—a lawn mower with a bagger will collect leaves and cut them into the perfect size for mulching.
You can spread a wood chip or shredded leaf mulch anywhere on your property, but it looks especially attractive in flower beds and shrub borders. Of course, it’s right at home in a woodland or shade garden. Wood chips aren’t a great idea for vegetable and annual flower beds, though, since you’ll be digging these beds every year and the chips will get in the way. They do serve well as a mulch for garden pathways, though.
Grass clippings are another readily available mulch, although it’s a good idea to return at least some of your grass clippings directly to the lawn as a natural fertilizer. It’s fine to collect grass clippings occasionally to use as mulch, and the nitrogen-rich clippings are an especially good choice for mulching vegetable gardens. Your vegetables will thank you for the nitrogen boost!
If you have enough compost, it’s fine to use it as a mulch. It will definitely enrich your soil and make your plants happy, but keep in mind that when any kind of mulch is dry, it’s not a hospitable place for plant roots. So you may want to reserve your compost to spread as a thin layer around plants and top it with another mulch, such as chopped leaves. That way the compost will stay moist and biologically active, which will provide maximum benefit for your plants.
Straw or hay
Another great mulch for the vegetable garden is straw, salt hay, or weed-free hay. It looks good and has most of the benefits of the other mulches: retaining soil moisture, keeping down weeds, and adding organic matter to the soil when it breaks down. But be sure the hay you use is weed and seed free, or you’ll just be making trouble for your garden. And don’t pull hay or straw up to the stems of vegetables or the trunks of fruit trees or you’ll be inviting slug and rodent damage.