A bed edger cuts a clean boundary between lawn and garden bed by tracing a marked line, cutting into the soil, and removing turf to form a distinct edge.
Whether carving a new planting area or refreshing an overgrown border, a bed edger is the tool for the job. The process takes about an hour for a typical bed, and doing it right once saves fixing sloppy edges all season. Here’s the sequence that works.
Before You Cut: Mark the Line and Check Underground
Call 811 before you dig — it’s free and required by law in most states. Also check for invisible dog fences and drainage pipes. Next, mark your edge line. For straight borders, drive stakes at each end and run string between them. For curves, lay a garden hose or rope on the ground in the shape you want. Spray paint along it to leave a visible line. Clear rocks, roots, and debris from the cutting path before starting, as a blade hitting a rock mid-stroke creates a jagged cut and can throw the tool sideways.
Using a Manual Bed Edger vs. a Powered One
The tool determines the technique, but both follow the same marked line.
Half-moon edger (manual): Place the blade on your painted line. Press down with your foot to drive it into the soil, then rock the handle forward and back to cut through grass roots. Fine Gardening recommends a first cut about 1½ inches deep, followed by a spade to deepen it to 4 to 6 inches at a 90-degree angle.
Powered bed edger: Set the wheels on the lawn side. Lower the blade into the ground, then walk backward slowly, guiding the tool along the marked line at a steady, moderate pace. Keep engine speed consistent and let the blade do the cutting.
Moist but not muddy soil gives the cleanest cut — dry soil crumbles; wet soil clogs the blade. For tool recommendations, see our tested roundup of the best mulch bed edgers.
Remove the Sod and Deepen the Edge
After the initial cut, remove the turf on the bed side to create the trench. For new beds, cut the turf inside the marked area into strips with a spade, then roll or lift them out, severing any deep roots. An effective two-step method: cut the outline first, then slice back at a 45-degree angle toward the bed. This removes triangular clumps and leaves a V-shaped trench that holds mulch better than a straight cut. Aim for a finished depth of 4 to 6 inches.
Cleanup and Maintenance
Rake loose soil and clippings into the bed or use a leaf blower to clear the trench. If adding mulch, the fresh edge acts as a natural dam. Do a major edge once per year in early spring or fall. Between sessions, maintain the line with a string trimmer every couple of weeks, walking so clippings land on the grass, not the bed.
| Mistake | Why It Hurts | The Fix |
|---|---|---|
| Skipping utility check | Hits gas lines, irrigation, or invisible fences | Always call 811 before any digging |
| Not marking the line first | Curves and straights become uneven | Use hose for curves, string for straight lines |
| Cutting with dry or wet soil | Crumbles or clogs; cut isn’t clean | Edge when soil is moist but not muddy |
| Moving too fast with power edger | Uneven depth and wobbly lines | Walk backward slowly, steady pace |
| Hitting hardscape with blade | Dulls blade instantly | Ease up near concrete, asphalt, and pavers |
| Skipping cleanup of loose sod | Leaves debris that looks unfinished | Rake or blow out the trench after cutting |
| Wrong trimmer-walk direction | Throws mulch into the grass | Walk so clippings land on the lawn side |
Safety and Tools
Wear gloves, eye protection, and closed-toe shoes. Power edger users should understand the tool’s safety features. Home Depot also recommends a face mask if sensitive to debris. Take care around curves, flower beds, pavers, and sidewalks — slow down to keep the line consistent.
FAQs
How deep should I cut the edge?
Most guides recommend a finished depth of 4 to 6 inches. The initial cut with a half-moon edger is about 1½ inches deep, then you deepen it with a spade until you reach a consistent 90-degree wall.
Can I use a string trimmer instead of a bed edger?
A string trimmer maintains an existing edge but won’t create a new one. Use it every couple of weeks between full edging sessions to keep the line sharp. Walk in the direction that throws clippings onto the grass, not into the bed.
When is the best time of year to edge beds?
Early spring and fall are the most common times for a full edge. During the growing season, touch up the edge two or three times as needed to keep grass roots from creeping back.
References & Sources
- Home Depot. “How to Edge a Lawn.” Covers marking, cutting technique, cleanup, and safety for manual and powered edgers.
- Fine Gardening. “Perfect Edges for Your Beds and Borders.” Details the half-moon edger depth, spade refinement, and seasonal maintenance schedule.
- Gardening Know How. “Using a Garden Bed Edger.” Explains two-step shovel method and V-shaped edge technique.