How to Mulch Like a Pro

Mulch does a host of things that your plants want and need, such as shading roots on hot days, preventing moisture from evaporating, and stopping weeds from taking root. But it’s important to learn the differences between mulch materials, and how to properly spread mulch.

Two Types of Mulch

There are two basic kinds of mulch: Organic and inorganic. Organic materials—wood, bark, compost, grass clippings, and leaves—will decompose and improve the soil. They last a few years, after which you’ll need to add more. In addition, organic mulches are easy to spread and do no harm if mixed into soil, as will happen when planting annuals or shrubs, for example.

Stone, by contrast, is meant to be a more or less permanent mulch, to be put in place atop a layer of landscape fabric and left alone. It’s the lowest-maintenance option but not easy to plant in. So the key question is: Will I be doing any gardening that requires digging and moving mulch aside to plant ornamentals? You’ll want to stick with organic mulch if the answer is yes.

Pick the Right Mulch

Every kind of organic mulch has pros and cons. For example, bark nuggets are widely available but can float away in heavy rain. Cocoa hulls have a distinct aroma (some like it, some don’t) but are relatively expensive and toxic to dogs. Shredded bark or wood is the most common landscape mulch—it’s inexpensive and easy to apply, but it doesn’t add as many nutrients to the soil as some other mulches.

You can also use waste from your yard as mulch, such as grass clippings, leaves, and compost. Compost adds a lot of nutrients but isn’t good at deterring weeds. If you compost at home, it’s not a good idea to use it to mulch flower beds unless you know that the compost got hot enough to kill weed seeds. Otherwise, you might end up with more weeds, not less!

Grass clippings are effective as mulch but don’t pile them too deeply, or they can get soggy and mucky. And be sure never to use clippings as mulch if the grass was treated with herbicides. Leaves are a practical example of how to mulch if they’re shredded first. Pine needles are long-lasting and an excellent mulch around acid-loving plants like azaleas because pine needles acidify soil.

Tips for Mulching

Although the process of mulching seems simple (you just put it over the dirt, right?), there are some things to keep in mind. These are some of our best mulching tips.

• Calculate how much mulch to buy. There’s nothing more frustrating than choosing the mulch you want and not having enough.
• Not too thick, not too thin. Lay down mulch about 2 to 3 inches thick. Anything thicker could harbor pests, but in any case, it’s wasteful and unnecessary.
• There’s no perfect time to apply mulch to beds. Your plants will welcome mulch any time of the year. If you apply mulch in late fall or early winter and you live in a cold climate, wait until the ground freezes before mulching.
• Mulch trees and shrubs properly. Mulching around trees and shrubs is a great way to prevent injury from mowers and trimmers. As with beds, spread mulch 2-3 inches thick. Do not pile mulch against the trunk like a volcano—this can encourage pests and diseases.