How to Edge a Lawn with a String Trimmer the Right Way
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The short answer
Rotate the trimmer head 90 degrees so the string cuts vertically, rest the guard against the pavement edge, and walk backwards along the line at a slow, even pace. Use 0.095-inch line for edging — thin line shreds against concrete. For hard-packed or overgrown borders, a blade edger still wins; string can only cut what it can reach.
0.095-Inch Trimmer Line
The minimum line weight that survives edging against concrete — twisted profile cuts cleaner than round.
The setup that makes string edging work
- Line: step up to 0.095-inch round or twisted line. The 0.065 and 0.080 line most trimmers ship with frays the moment it touches concrete.
- Angle: head vertical, string tip just kissing the soil line. Riding the guard against the hardscape keeps the depth consistent.
- Direction: walk backwards, pulling the trimmer toward you. The string throws debris away from your legs and you can see the line you're cutting.
- Speed: one slow pass beats three fast ones. Fast passes bounce the head and scallop the edge.
Where string edging falls short
String cuts grass blades and soft stolons — nothing more. It cannot slice compacted soil, established Bermuda runners or a border that's been neglected for a season. For those, you need a blade: a Radius Garden Half-Moon Edger for short runs or a dedicated stick edger for a full property. Most pros reset with a blade once a season and maintain with string between.
Frequently Asked Questions
- Can you edge a lawn with a weed wacker?
- Yes, for maintained borders on soft grass. Rotate the head vertical, use 0.095-inch line and walk backwards slowly. What it can't do is cut a new trench in compacted soil — that takes a blade.
- Why does my trimmer line keep snapping when I edge?
- You're either running line that's too thin, or feeding it into the concrete instead of the soil line. Step up to 0.095-inch line and let only the last half-inch of string touch the ground.
- Is a blade edger better than a string trimmer for edging?
- For cut quality and overgrown borders, yes — a blade cuts a true vertical trench. String wins on speed and convenience for weekly touch-ups on already-established edges.
The Gear We’d Buy
Everything referenced in this guide, in one place.
0.095-Inch Trimmer Line
EssentialThe minimum line weight that survives edging against concrete — twisted profile cuts cleaner than round.
Typically $15 - $25
Padded Shoulder Strap
Rotated-head edging torques your forearms — this moves the load to your shoulder.
Typically $15 - $30
Radius Garden Half-Moon Edger
Reset toolWhen the border is compacted or overgrown, string can't cut it — this can, in one pass.
Typically $40 - $60
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Key Takeaways
- 0.095-inch line is the minimum for edging against concrete.
- Walk backwards, guard against the pavement, one slow pass.
- String maintains an edge; only a blade can create one.
- A shoulder strap saves your forearms on rotated-head work.
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 in 5 Steps (Without Scalping It)
The exact depth, angle and pass sequence for edging along sidewalks, driveways and beds — whether you use a stick edger, a half-moon tool or a string trimmer.
How to Install Landscape Fabric So It Stays Put
Overlap, staple spacing and edge anchoring decide whether landscape fabric lasts a decade or lifts by August. Step-by-step spacing numbers inside.
Sharpening a Half-Moon Edger
The file angle, stroke direction and burr check that turn a dull manual edger back into a tool that slices sod instead of tearing it.
Essential
0.095-Inch Trimmer Line