Your Ultimate Guide to Mulching

Landscape fabric, made from polyester or polypropylene, is used to manage weeds. Schlegel says it’s often a better choice as it's more durable and sturdy than plastic, depending on the brand. 

Schlegel explains the downside of inorganic mulch is that it doesn't add important nutrients to the soil and feed the microorganisms.

How to mulch for a cut-flower or vegetable garden? 

Mike Belleme

If you are growing an edible garden or cut-flowers, straw or leaves are the best option. Rake up your leaves in the fall to use as a natural and free mulch. 

“I will use leaves from the previous fall as a mulch around the base [of the plants] that keeps weeds down and it slowly feeds the soil [and] keeps the soil moist,” Schlegel says.

Another option is to purchase straw — not hay — from your local garden center. What’s the difference? Hay can introduce a lot of weeds into your soil, Schlegel says. Straw, however, regulates soil temperature and prevents diseases from spreading by keeping fruits such as melons, cucumbers, squash and strawberries from touching the ground. 

Experts recommend placing 2 to 3 inches deep of straw or leaves from the soil line. 

Along with hay, avoid wood chips in an edible garden. Fresh wood chips will steal a lot of the nitrogen out of the soil — and nitrogen is key to your garden plants’ health, Meyer says. 

Flowers, trees and shrubs

Pine bark and wood chips are a good option for small shrubs, trees and perennials, Schlegel says. 

“Your best bet is to go to a local nursery for mulch that's produced on site,” Meyer says. “You'll have options for the quality of the mulch — either single, double or sometimes triple shred, which means that they've put that mulch through the machine three times.”

Garden centers also sell bagged mulch. Double-shredded is the most common to use for shrubs and trees, he says. 

When and how to mulch

The best time to mulch is after you've planted, so typically in the spring and fall.

“In the early spring, it's easier to apply [mulch] before the plants really sprout up, if you're talking about perennials,” Mizejewski says.  

Mulching is simple as long as you follow some guidelines. You don't want it to touch plant stems or tree trunks as this can lead to fungal diseases and rotting. For plants, place mulch a couple of inches away from the plant stem and for trees several inches away from the trunk. The amount of mulch to use depends on if it's an edible garden, shrubs or trees.  

Mike Belleme

Shrubs and trees. Give the base of your tree and shrub a little space, Meyer says. Keep the mulch 4 to 5 inches from the trunk and make the mulch about 1 to 2 inches deep.

What you don’t want to do is what is called “volcano mulching” he adds. That’s where you pile up wood chips at the base of the trunk, which keeps the trunk constantly moist, attracting disease, insects and rodents. 

Mike Belleme

Vegetable or flower gardens. The rule of thumb for mulching a vegetable or flower garden is to add a layer around 2 to 3 inches deep. You want just enough mulch so the soil isn’t bare, without smothering plants. “It is going to break down and it will compost naturally and … will slowly return nutrients into the soil,” Mizejewski explains.

After you mulch an area, give it a good watering.

Mike Belleme

“You want to moisten them all, which will help weigh [the mulch] down, so if there’s any loose bits they won't kind of blow around,” Mizejewski says. Make sure mulch doesn't get too dry as this can prevent water from reaching the roots.

“Some mulches, if they get really dry, almost serve as a barrier for water getting to the ground,” he says. 

Mulch is also aesthetically pleasing by making the landscape look clean and defining a garden bed or creating a border.

“People use mulch to achieve a particular look in their landscape or their garden for a neat and tidy appearance,” Mizejewski says.