To use a string trimmer as an edger, rotate the trimmer head 90 degrees so the cutting string runs vertically instead of horizontally. Walk along the edge while keeping the spinning string parallel to the hard surface. This technique creates clean lines along sidewalks, driveways, and flower beds without needing a dedicated edger tool.
Understanding Edging with a String Trimmer
Edging and trimming serve different purposes in lawn maintenance. Trimming involves cutting grass that extends beyond the desired mowing height, typically while holding the trimmer with the string rotating horizontally. Edging, on the other hand, creates a clean vertical cut where the lawn meets hard surfaces like concrete, brick, or wood borders.
Many homeowners own a string trimmer but not a dedicated edger. Using your existing trimmer for edging saves the cost of purchasing another tool and works well for regular maintenance of lawn edges. The technique works by repositioning the trimmer head so the cutting string contacts the grass from the side rather than from above.
The method works best for light to moderate edging tasks. If your lawn edges are already established and you maintain them regularly, a string trimmer handles the job effectively. However, very hard or compacted soil, deeply rooted grasses, or edges that have not been maintained for a long time may prove challenging with this approach.
Before You Start: Setup and Safety
Proper preparation prevents accidents and ensures better results. Begin by reading your trimmer’s manual to confirm whether your model includes an edging position and how to activate it. Many string trimmers feature a rotating head that locks into place with a push-button, collar twist, or lever mechanism.
If your trimmer does not have a dedicated edging mode, you can still perform edging by manually rotating the head. Some models require holding the head at an angle rather than locking it completely. Understanding your specific tool’s capabilities helps you work safely.
Choosing the Right Cutting Line
The gauge and type of cutting line affect edging performance. Thicker, heavier-gauge line generally holds up better when edging because it resists breaking against hard surfaces. Round line works for general use, while serrated or twisted line can provide a more aggressive cut in tough conditions.
Replace worn or old line before edging. Frayed or weak line reduces cutting efficiency and may break more frequently during operation.
Safety Equipment
Edging with a string trimmer throws debris in a different direction than horizontal trimming. The vertical string projects grass clippings, soil, and small stones outward from the cutting path. Wear safety glasses or goggles to protect your eyes. Long pants and closed-toe shoes provide protection for your legs and feet. Work gloves help maintain grip and protect your hands.
Lawn Conditions
Dry grass produces a cleaner cut when edging. Wet grass tends to clump and can create an uneven line. Additionally, wet conditions make the work surface slippery and increase the risk of slipping while operating the trimmer. Plan to edge after the lawn has dried from rain or morning dew, typically in the late morning or early afternoon on dry days.
Step-by-Step: How to Use a String Trimmer as an Edger
Step 1: Rotate the Trimmer Head
Power off the trimmer completely and allow the engine or motor to stop if applicable. For gas or electric trimmers with a rotating head, locate the mechanism that holds the head in trimming position. Engage the release and rotate the head 90 degrees so the cutting string will spin in a vertical plane rather than horizontal. Lock the head firmly into the edging position.
If your trimmer lacks a locking mechanism, simply hold the head at a 90-degree angle throughout the edging process. Maintain a consistent grip and angle to produce an even line.
Step 2: Position the Trimmer Correctly
Stand to the side of the trimmer rather than directly behind it, since debris will fly outward from the edge. Hold the trimmer so the spinning string is parallel to the hard surface you are edging. The string should be the part closest to the hard surface, with the trimmer body angled slightly away from you.
Tilt the top of the trimmer slightly backward so the bottom tip of the string contacts the ground at the correct angle. This creates the shearing action needed for a clean cut. The exact angle depends on your trimmer model and the height of the grass, but generally, the string should approach the grass at roughly a 45-degree angle relative to the ground.
Step 3: Use Guides if Available
Some string trimmers include an edge guard, guide wheel, or edger attachment. The edge guard is typically a curved piece of plastic that sits between the string and the trimmer body, preventing the string from cutting too deep or contacting the hard surface excessively. A guide wheel rolls along the edge and helps maintain consistent depth and distance from the curb or sidewalk.
If your trimmer has these features, engage them for more consistent results. If not, use the trimmer housing or a fixed point on the tool as a visual reference for maintaining distance.
Step 4: Walk and Cut Along the Edge
Start the trimmer and bring the engine or motor to full speed. Walk slowly along the edge, letting the spinning string do the cutting work. Do not force the trimmer forward. Allow the string to contact the grass at its own pace. Walking too fast produces an uneven, ragged line.
Maintain a steady pace that matches the cutting speed of the string. For most trimmers, this means moving at roughly a normal walking speed while focusing on keeping the string parallel to the edge.
Step 5: Handle Curves and Corners
For curved edges, pivot your body rather than bending the trimmer. Keep the head angle consistent and rotate your stance to follow the curve. For inside corners where two edges meet, stop at the corner and lift the trimmer slightly to clean the remaining grass. For outside corners, continue the curve smoothly without stopping.
Straight runs along sidewalks and driveways are straightforward: simply walk forward while maintaining the string position. Pause occasionally to check your progress and ensure you are cutting at the desired depth.
Techniques and Troubleshooting for a Clean Edge
Maintaining Consistent Depth
Keep the bottom of the cutting string just touching the soil line where the grass meets the hard surface. Pressing too deep digs into the soil and creates a trench. Letting the string ride too high leaves uncut grass at the top of the edge.
Practice on a small section first to calibrate the correct depth before continuing along the entire edge. Adjust your tilt angle as needed to maintain consistent contact.
Preventing String Breakage
String breakage occurs more frequently during edging than during horizontal trimming because the string contacts hard surfaces directly. Use a heavier gauge line to reduce breakage. Keep the string at the proper length—too short reduces cutting efficiency, while too long causes the string to bend and tangle.
Check the line periodically during long edging sessions and advance fresh line as needed. Many trimmers allow you to tap the head on the ground to advance line automatically.
Fixing Uneven Edges
If your edge comes out wavy or uneven, the most common cause is inconsistent walking speed or angle. Practice maintaining a steady pace and a consistent tilt angle. Work in overlapping passes if a single pass does not clean the edge completely.
For particularly uneven areas, go back over the section with slower, more deliberate movements. Mark the desired edge line with a board or rope as a guide if needed.
Managing Debris
Grass clippings and soil will scatter onto the sidewalk or driveway during edging. Rake or sweep the area after finishing to collect debris. Working in a systematic pattern—edging an entire section before moving to the next—helps contain the mess.
If debris consistently lands where you have already cut, adjust your direction: start from one end and work toward the other, so you always cut into clean territory.
String Trimmer vs. Dedicated Edger: When to Use Which
A string trimmer used as an edger works well for regular maintenance of existing edges. If you edge your lawn every one to two weeks during the growing season, the trimmer method keeps edges tidy without significant effort. This approach also works well for curved beds and irregularly shaped edges where a wheeled edger would be difficult to maneuver.
A dedicated edger with a steel blade provides cleaner results in challenging conditions. Hard, compacted soil, thick root systems, or deeply worn edges that have not been maintained for some time respond better to a blade edger. If you find that your trimmer struggles to cut through the turf at the edge, leaving a ragged or incomplete line, a dedicated edger may be worth the investment.
Edger attachments for string trimmers occupy a middle ground. These accessories replace or augment the trimmer head to provide a blade or wheel-guided cutting system. They offer better results than string alone in difficult conditions while eliminating the need for a separate tool.
Consider the trade-offs of cost, storage space, and frequency of use. If you have limited storage and only need edging occasionally, the trimmer method likely suffices. If you maintain formal lawn edges that demand a crisp, professional appearance, a dedicated edger or attachment may justify the expense and space.
Final Tips and Maintenance
How Often to Edge
Weekly edging during active growth seasons keeps lawn edges clean and defined. In slower growth periods, edging every two weeks maintains the appearance. Adjust frequency based on your grass type and growing conditions.
Trimmer Maintenance After Edging
Edging puts extra wear on the trimmer head and line. Inspect the head for damage or debris buildup after each use. Clean grass and soil from the ventilation slots if applicable. Replace worn line before the next use. Check that all fasteners remain tight and that any rotating mechanisms operate smoothly.
Best Timing for Edging
Late spring through early fall typically offers the best conditions for edging in most climates. Edge after mowing the lawn so the cut grass does not interfere with your work. As mentioned earlier, dry conditions produce cleaner cuts and reduce slipping hazards.
Morning hours often provide calm conditions that help you see the edge line more clearly, but wait until dew has evaporated. Late afternoon works well if the grass has dried from midday warmth.
Frequently Asked Questions
Can all string trimmers be used as edgers?
Most string trimmers can perform edging to some degree, either through a dedicated edging position or by manually rotating the head. However, some lightweight or entry-level models may not lock securely into an edging position, making the technique more difficult to execute consistently.
Do I need to remove the guard when edging?
This depends on your specific trimmer model. Some guards are designed to work in both trimming and edging positions. Others may obstruct the cutting line in edging mode. Consult your manual to determine whether the guard should remain in place, be repositioned, or be removed during edging.
Why does my edge look ragged after using the trimmer?
Ragged edges usually result from inconsistent speed, angle, or string condition. Ensure the string is fresh and at the proper length. Walk at a steady pace and maintain a consistent tilt angle throughout the pass. Consider using heavier-gauge line for tougher grass.
Is edging with a string trimmer harder on the equipment?
Edging places more direct stress on the cutting line than horizontal trimming because the string contacts hard surfaces regularly. Line wear increases, and the head mechanism may experience additional stress. Regular inspection and maintenance help manage this additional wear.
