Difference Between String Trimmer and Edger | Lawn Lineup

Standing at the curb with a tool that’s clearly not cutting the crisp line you wanted, the difference between a string trimmer and an edger becomes painfully obvious. One wrong tool choice turns a twenty-minute job into a frustrating hour. Here’s the breakdown you need to decide which one belongs in your shed, and whether a combo unit makes sense.

What Each Tool Does Best

A string trimmer spins flexible nylon line at high speed to knock down grass and weeds in places a mower can’t reach. It handles fence lines, tree bases, foundations, and tight corners with ease, making it the more versatile tool for routine cleanup. Most people use it with the head parallel to the ground.

A dedicated edger, on the other hand, uses a rigid blade positioned vertically to cut a precise, defined groove between your lawn and the sidewalk or driveway. It creates that manicured, landscaping-professional border that a trimmer simply can’t match, because the trimmer’s flexible line flexes instead of cutting cleanly into turf.

Here’s the practical result: trimmers are faster and more versatile for general maintenance; edgers produce a sharper, more polished line along hard edges. If you want that crisp “golf course” look, you need an edger.

Can a String Trimmer Do the Job of an Edger?

Yes, but you’ll trade away some quality. Many homeowners get by using a string trimmer in edging mode, where you rotate the head vertically and walk the spinning line along the pavement. It works for light touch-ups, and it saves you from buying another tool.

Yet the cut is rarely as clean. The flexible line feathers the edge instead of slicing it, and it struggles to cut deeper into compacted soil where turf meets concrete. The line also wears down quickly when it scrapes against pavement, meaning you’ll feed more line and get an inconsistent result. Bob Vila’s guide on the topic notes that trimmers handle light edging, but a dedicated edger makes a cleaner, more defined line.

How to Switch Your Combo Tool Between Modes

Combination trimmer/edger units let you own one tool that does both jobs, but only if you switch the head correctly. Greenworks manuals describe two common mechanisms depending on the model.

Some convertible models use a collar system: you turn the collar and rotate the lower housing 180 degrees to lock the head into edging position. Others use a foot pedal: you remove the battery pack, step on the pedal to release the head, and rotate it counterclockwise into the vertical edger position.

Here’s the catch that catches most first-timers: always power down the tool or remove the battery before switching modes. Rotating the head while the line is spinning is a fast way to strip the gears or pinch a finger. Also, make sure the head clicks fully into the edger position before you pull the trigger—running it halfway between modes gives you a wobbly, useless cut.

When you do edge, take light, slow passes. Trying to carve the whole border in one aggressive sweep removes chunks of turf and leaves a ragged gouge instead of a clean groove. Two or three gentle passes beat one violent one every time.

If you’re shopping and want one machine that handles both chores without compromise, our tested roundup of the best edger trimmer combo tools breaks down which models switch modes cleanly and which ones feel flimsy in practice.

String Trimmer vs. Edger: Which Should You Buy?

Your yard’s layout decides this. If you have lots of obstacles—trees, flower beds, fences, a mailbox—a string trimmer is the workhorse you’ll use every week. It’s the more versatile tool and the better first purchase for most homeowners.

If you have long stretches of sidewalk, a driveway, or defined garden borders and you want that crisp, professional edge, a dedicated edger earns its place. It does one thing, and it does it superbly.

For those who want both without owning two machines, a convertible combo unit is a legitimate middle ground, especially for smaller yards where switching modes a couple of times per mow isn’t a hassle.

Note that some “edge trimmer” advice you’ll read refers to a string trimmer used in edging mode, not a separate blade edger—know which one the article is talking about before you follow its steps.