How to Mulch the Right Way
There are plenty of reasons to add mulch to your garden beds. Not only does it provide aesthetic beauty, but a layer of mulch can greatly benefit your plants—when applied properly, that is. Mulch's benefits are quickly cancelled out if you put it down incorrectly. Ahead, how to avoid common pitfalls and maximize your efforts.
Understand mulch's benefits.
Mulch is a two- to three-inch layer of organic material that is placed down over a garden bed's soil; it slows evaporation and water runoff, moderates ground temperature fluctuations, and enriches soil as it breaks down, says Hank Bruno, a horticulturist and grounds manager with Services for Education. "It can also suppress weed seed germination if the beds are cultivated before application," he says, which is why so many people add it to their landscapes.
Prepare the area.
If you're putting mulch beneath shrubs or hedges, it's best to prune your plants first and clean up your clippings before getting started. "If your shrubs have been plagued with insects or disease problems, remove the infected leaves and flowers before applying mulch," he says. "Many diseases and insects overwinter in the soil, so it is important to remove the detritus to prevent future problems." If you're adding annuals to your garden, place the mulch over the tilled beds prior to planting, pulling the layer back as you go. "This prevents mulch from covering young plants," he says. "It also avoids soil compaction if you must step in the bed to distribute mulch."
Choose the right type of mulch.
There are plenty of mulch options to choose from, but Bruno says organic is always better than synthetics like plastic, fabric, or rubber. "In the South, we use pine needles (or pine straw) and pine bark. Hardwood chips are used in the Mid-Atlantic region and salt hay is used on the East Coast," he says, noting that "mushroom compost makes excellent mulch, and shredded pinecones are inexpensive, elegant, and long-lasting." And while wheat straw can work well, be aware that the seeds will germinate, he says—and you will find yourself pulling out wheat seedlings.
Opting for wood mulch? Select natural, dye-free chips.
"When using wood chips or sawdust, it is best to find an old pile that is well rotted. Actively decomposing wood will heat up and consume nitrogen in the process of breaking down," Bruno says, adding that dyed iterations aren't worth your time. "Chips that are dyed red or black look unnatural and are jarring in the landscape; the darker the color, the more heat they will absorb." He suggests choosing natural, dye-free chips that will keep the attention on your plants, not the mulch.
Skip the landscaping fabric.
While landscaping fabric may sound like a good idea, you should only use it if you are willing to remove it in two years' time, says Bruno, when the weeds and grass have grown through it (which they will). At that point, the only way to uproot and remove them would be take away the fabric, which can be an exhaustive endeavor.
Apply your mulch layer evenly.
The number one mistake that gardeners make when they apply mulch to their landscapes? Building "volcanoes" around their trees, notes Bruno. "This is detrimental to tree health for several reasons," he says. "The deep mulch encourages tree roots to come to the surface in search of moisture and piling mulch against the trunk invites insects that can bore into the trunk and damage it." You absolutely can mulch your trees so long as the material is coarse, is kept away from the bark, and is not mounded up around the trunk. "A generous tree ring prevents mower and string trimmer damage and helps retain moisture in the soil, provided it is done properly," he adds. The same rings true for mulching your other plants: Always apply layers evenly, without loading too much material against their base.