A neat edge between your lawn and garden bed is one of the simplest ways to make your whole yard look well-maintained and intentional. With the right tools and a bit of technique, you can achieve a crisp, professional-looking border that's easy to maintain throughout the season.
Why Edging Matters
Beyond looks, a well-defined edge stops lawn grass from creeping into your garden beds and keeps mulch or soil from spilling onto the lawn. In many parts of New Zealand, warm-season grasses like kikuyu and buffalo are particularly aggressive spreaders — a clean edge is your first line of defence against them taking over your garden beds.
Tools You'll Need
Choosing the right tool makes all the difference:
- Half-moon edging iron – The classic hand tool for cutting a sharp, vertical edge into soil. Great for redefining an overgrown border.
- Long-handled edging shears – For trimming grass that overhangs an existing edge without bending over.
- Rotary lawn edger – A wheeled hand tool that rolls along the lawn edge and cuts a consistent line. Good for straight or gently curved borders.
- Power edger or line trimmer – Faster for long runs. A line trimmer held vertically works well, though it takes practice to keep the line straight.
- Spade – Can substitute for a half-moon edger in a pinch, though the curved blade makes a less precise cut.
All of these are available at Bunnings or Mitre 10. For occasional use, a half-moon edger and long-handled shears are all most homeowners need.
Step-by-Step: How to Edge a Garden Bed
1. Mark Your Line
Before you cut, define where you want the edge to be. Use a garden hose or rope to lay out a smooth, flowing curve, or a length of timber as a straight guide. Step back and look at it from a distance before committing.
2. Cut the Edge
Using your half-moon edger or spade, push straight down into the soil along your marked line — aim for a depth of around 50–75 mm. Keep the tool vertical so you get a clean, upright face rather than a sloped cut. Work in small steps, overlapping each cut slightly.
For an existing edge that just needs tidying, a rotary edger or line trimmer held vertically is quicker.
3. Remove the Spoil
Lift out the cut turf and soil. This material can be composted or used to fill low spots elsewhere in the lawn. Don't leave clumps on the lawn — they'll smother the grass.
4. Trim the Overhang
Use long-handled edging shears to snip any grass blades that hang over the cut edge. Work along the border, keeping the blades flat and parallel to the ground.
5. Clean Up
Sweep or rake loose soil and clippings off the lawn surface. A leaf blower works well for this. Finish by applying a layer of mulch (bark, wood chip or pea straw) to the garden bed right up to the edge — this helps suppress weeds and defines the border visually.
Keeping the Edge Sharp Over Time
| Frequency | Task |
|---|---|
| Every 2–4 weeks (growing season) | Trim overhanging grass with edging shears or line trimmer |
| Every 2–3 months | Re-cut the vertical face with a half-moon edger or spade |
| Annually | Redefine the full edge and top up mulch |
In New Zealand's warmer northern regions, kikuyu and couch grass can blur an edge within weeks during summer, so stay on top of it during the growing season (roughly October to April).
Physical Edging Strips: A Low-Maintenance Option
If you want to reduce ongoing maintenance, consider installing a physical edging strip along the border. Options include:
- Steel or aluminium edging – Sleek, long-lasting, and very effective at stopping grass runners. Requires pinning into the ground.
- Plastic lawn edging – More affordable and flexible for curves. Quality varies, so choose a heavier gauge.
- Timber sleepers or boards – Attractive and natural-looking, though timber will eventually rot. Use treated timber rated for ground contact.
- Concrete mowing strips – A permanent solution that also lets you run a mower wheel along the edge. Usually requires a bit more effort to install correctly.
Physical edging strips are widely available at Bunnings, Mitre 10 and PlaceMakers.
Tips for Curves and Corners
- Use a garden hose to lay out smooth curves — it's flexible and easy to adjust before you cut.
- For tight inside corners, use a half-moon edger and work from both directions to meet in the middle.
- Avoid overly complex shapes; gentle curves are easier to maintain and look more natural.
Safety Notes
- Wear sturdy closed-toe footwear when using edging irons or spades — a slip can cause a serious foot injury.
- If using a power line trimmer, wear eye protection and long trousers to guard against flying debris.
- Check for buried irrigation lines or cables before cutting deep into the soil, especially in established gardens. If in doubt, dig carefully by hand first.
When to Call a Professional
Most garden edging is well within DIY reach. However, consider hiring a qualified landscaper if:
- You're redesigning a large or complex garden layout and want the edging to integrate with new planting, paving or irrigation.
- You want to install a concrete mowing strip or raised garden bed edging that involves significant earthworks or structural elements.
- You're unsure about buried services (irrigation, lighting cables) in your garden.
A professional landscaper will have the tools and experience to get the job done efficiently and to a high standard. You can find qualified local landscapers on tradedirectory.co.nz.
Licensed Building Practitioner (LBP)
