Mulching is an important part of gardening, helping to keep your plants and flowers healthy. But before you jump in, you should know that there's a right way to mulch and a wrong way to mulch, and using incorrect methods can actually hurt your garden.
Why you should mulch
Mulching might seem like an extra step that extends the gardening process, but it can actually save time. Using mulch in your garden will make it healthier, weed-free, and more drought-resistant,” says Susan Brandt of Blooming Secrets, an e-commerce gardening website. And this, in turn, helps you garden more efficiently. You spend less time watering, weeding, and fighting pests.
Besides making your garden look good mulching provides other benefits:
Retains soil moisture so the soil doesn’t dry out.
Suppresses weeds (with a thick enough layer of mulch, the sunlight does not reach the soil, preventing seeds from germinating).
Insulates the soil from cold and hot weather by acting as a protective blanket.
Keeps soil from splashing up on flowers and vegetables.
Encourages earthworm activity, which improves nutrient content.
Kinds of mulch
Mulch is available in organic and inorganic varieties. Organic mulch includes previously living material, such as straw, grass clippings, chopped leaves, compost, wood chips, shredded bark, and pine needles. Inorganic mulch includes such things as gravel, stones, and black plastic.
While both types of mulch depress weed growth, organic mulch will enhance the soil as it decomposes. But there are also reasons to use the inorganic variety. Some will keep the soil warm and emit heat in the evening, and this is good for heat-loving vegetables, such as tomatoes and eggplants.
It’s important to understand that the kind of mulch you use—the color, type, and even weight—can make a huge difference. Pine-bark nuggets may be too large for a bed of annuals, but perfect for an area around trees or shrubs,” says Lester Poole, live nursery specialist at Lowe’s. Also, if you’re using mulch in an area that slopes or is prone to high winds or flooding, he recommends using a heavier or larger material in your landscaping that is less likely to be blown away.
Purchasing or finding mulch for free
When buying mulch, it can be difficult to determine how much you’ll need. Start by measuring the space you need to cover. A 2-cubic-foot bag covers an area of 8 square feet. One cubic yard of mulch covers an area of 108 square feet.
However, you don’t always have to buy. You can use grass clippings, as long as you don't apply them too thickly (since they can get soggy). Don’t use grass clippings if you've treated your grass with an herbicide.
How to mulch
Before you start, put on work gloves to protect your hands from splinters if you’re using bark and wood chips.The recommended depth for proper mulch covering is 3 inches to 4 inches, according to Steven Voss, owner of Voss Land & Tree in Columbia, MO. After the mulch has been spread, pull it away from the base of any plants. “This crucial step will create a ‘doughnut hole’ around the base of the plant and avoid the mulch volcanoes,” he says, meaning heaped pyramids of mulch that can stifle growth. However, you want the mulch to go out as far from the base as the branches do. “This is called the dripline: The moisture that drips from the branches of the plant should drip down into the mulch and keep your plants happy," Voss says.
Pro tip! To make mulching easier, Daniel Scott, associate director of Horticulture & River Farm at the American Horticultural Society in Alexandria, VA, suggests turning those empty pots upside down over the tops of your newly planted foliage. “Mulch directly over the tops of the pots, and when you remove them, you will have a beautifully mulched bed, without mulch all over your plants,” he says.
Scott also likes to use a rake to smooth out the mulch and tidy up the bed. “After mulching, turn the rake over and hold it at a low angle, almost parallel to the ground, and pull it towards you.” He recommends a four-tined, long-handled pitchfork as a very efficient way to place the mulch exactly where you want it.
Don't apply too much mulch
While mulch is good for your garden, too much of a good thing can ruin it. “Too much mulch can inhibit water percolation down into the soil, and therefore into the root zone of the plant,” warns Scott. “Sometimes it may be necessary to rake out your old mulch before applying a fresh layer, but, in general, it is OK to top-dress your existing mulch with a light 1-inch to 2-inch layer.”
How often should you mulch?
Be careful not to mulch too soon. If the soil is too cold, seedlings may not be able to penetrate a deep layer of mulch.
Scott advises mulching twice a year: once in late winter or early spring, and once again later in the year. "This allows you to replenish any mulch that has degraded over the season and give your yard a nice clean look,” he says.
Information from: Terri Williams, journalist who has written for USA Today, Yahoo, the Economist, U.S. News and World Report, and the Houston Chronicle.