Edger or String Trimmer — Which Actually Cuts a Border?
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The short answer
A blade edger is the only tool that cuts a clean vertical edge, because it drops a hardened steel blade into the soil to a set depth. A string trimmer turned on its side shaves the grass blades back but leaves the soil line untouched — that is why trimmed edges look ragged within a week and creep over the concrete within a season. Use a trimmer to maintain an edge you already cut; use an edger to create or reset one.
EGO Power+ 15" Edger
A dedicated blade edger with five depth stops — the tool that actually cuts the trench a trimmer cannot.
The two tools look interchangeable in a store aisle and are not interchangeable in a yard. The difference is not power, it is geometry: an edger cuts down into soil at a fixed depth, and a trimmer cuts grass in the air with a spinning line.
What each tool physically does
| Blade edger | String trimmer (turned sideways) | |
|---|---|---|
| Cuts soil | Yes — 1 to 3 in deep, depth-stopped | No, only surface grass |
| Edge shape | Vertical trench with a defined lip | Feathered, rounded |
| How long it lasts | 3 to 4 weeks between passes | 5 to 10 days before it blurs |
| Fixes turf creeping over concrete | Yes | No |
| Debris | Soil clods, thrown low | Grass mist, thrown everywhere |
| Best use | Cutting and resetting the line | Touch-ups between edging |
Why a trimmer edge disappears
Turf spreads horizontally by stolons and rhizomes just under the surface. A trimmer never touches that layer, so the runners keep advancing under the concrete lip. Two months of trimmer-only edging and the pavement is a half inch narrower than it was.
Myth
A powerful trimmer with a hard line does the same job as an edger.
The Fact
Line flexes on contact with soil. Even a heavy 0.095 in line skates across a compacted edge instead of cutting into it — you get a shaved edge, not a trench.
When a trimmer is genuinely enough
- Your borders are all soft — mulch beds, gravel, garden edging — with no concrete lip to protect.
- You already cut a real edge this season and just want it tidy for a weekend.
- The run is under about 40 feet and you edge it every single week.
- You are trimming around obstacles: posts, downspouts, tree rings, meter boxes.
The practical combination most yards want
- 1Cut the border with a blade edger at a 1.5 to 2 in depth setting, walking with the guide wheel riding the concrete.
- 2Blow or sweep the soil clods back onto the lawn before they dry into a crust on the driveway.
- 3For the next three or four mows, keep the line honest with a trimmer held vertically.
- 4Re-run the edger once the trench lip starts to round over, usually monthly in growing season.
What about a trimmer with an edger attachment?
Split-shaft systems with a genuine blade edger attachment are a real edger — the attachment carries a steel blade, a depth guide and a wheel. What they trade away is balance: the pivot point is far from the blade, so holding a consistent depth over a long run takes more effort than a dedicated stick edger. For borders under about 150 feet, that trade is worth the money and shed space.
The Gear We’d Buy
Everything referenced in this guide, in one place.
EGO Power+ 15" Edger
Top pickA dedicated blade edger with five depth stops — the tool that actually cuts the trench a trimmer cannot.
Typically $180 – $230 bare tool
Worx WG896 Corded Edger
Best valueCheapest honest way to get real blade depth if your borders sit inside cord range.
Typically $90 – $120
Radius Garden Half-Moon Edger
For short borders, a sharp half-moon blade cuts a cleaner line than any trimmer.
Typically $40 – $60
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Key Takeaways
- Only a blade edger cuts soil; a trimmer cuts grass in the air.
- Trimmer-only edges blur in about a week and let turf creep over concrete.
- Cut with the edger, maintain with the trimmer — that pairing beats either tool alone.
- An attachment-style edger is a real edger, just harder to hold at a constant depth.
Reviewed by
The Lawn Tool Hub Test Bench
We buy, borrow and break lawn tools on our own yards — clay in the back, sand-cut Bermuda in the front — and write down what actually changed the result.
Keep reading
How to Edge a Lawn for the First Time
The exact order of operations for a first edging pass: depth setting, which direction to walk, what to do with the soil, and the two mistakes that ruin a new border.
Best Edger for Thick, Overgrown Borders
Overgrown edges need blade depth and torque, not a trimmer. Here is what cuts through matted Bermuda and turf that has crept over concrete — and the two-pass method that saves the blade.
Ryobi vs. EGO vs. DeWalt: Which Cordless Edger?
A straight comparison of the three battery platforms homeowners actually own: blade depth, weight, runtime and which one is worth buying if you already have the batteries.
Top pick
EGO Power+ 15" Edger