Illustration of how to use your string trimmer as an edger
Illustration: Rodrigo Damati

In addition to cutting tall grass in hard-to-reach spots, your string trimmer can also function as an edger to give your yard a professionally landscaped look. Edging creates a crisp line, free from grass and weeds, along the edge of a patio or walkway. “Edging elevates the look of your lawn, but not everyone knows that a string trimmer is the perfect tool to do it,” says Misha Kollontai, who tests them for CR. “It’s usually as easy as holding the tool on its side and making a few quick adjustments.”

To start, hold your string trimmer at a 90-degree angle so that the line spins top to bottom instead of side to side. Lower the spinning line until it just comes into contact with the soil and grass along the edge of your walkway. It will dig out a crisp line of soil, removing grass and weeds, and prevent them from growing back by uprooting any seeds or roots in the process.

Some string trimmers are better suited to this task than others. When we tested models for how well they edge, many of the less powerful battery trimmers got bogged down by dirt. But some, like the BESTE620 from Black+Decker, have a small wheel (or wheels) so that you can easily roll the angled trimmer along the edge, cutting as you go.

More on String Trimmers

You’ll also need to take a few safety precautions. The tools may look harmless compared with a chainsaw or lawn mower, but string trimmers and other powered grass trimmers can cause injuries resulting from flying debris, like gravel. And their thick nylon cutting lines spin at up to 10,000 rpms, notes Don Huber, CR’s director of product safety. “That speed is easily dangerous enough to cause serious lacerations,” he says.

Every string trimmer comes with a shield to deflect grass trimmings and small rocks from shooting up at the user, but you also need to make sure the string is spinning away from you as you work. Otherwise you can kick up small rocks and dirt toward your face. Never trim near children, pets, or bystanders. And always dress appropriately: long pants and closed-toe shoes, gloves, safety goggles or glasses to protect your eyes, and hearing protection.

If you use a gas-powered string trimmer, never start the tool in the garage—carbon monoxide can build to dangerous levels quickly, even if the door is open. If you use a corded model, be mindful that you don’t accidentally cut the cord or trip on it while trimming.

Editor’s Note: This article also appeared in the June 2020 issue of Consumer Reports magazine.