Measuring the edge
Edging is bought by length, so the only measurement that matters is how long the edge is:
pieces = ⌈ edge × (1 + allowance) ÷ piece length ⌉
For curved beds, mark the line first with a rope or marking paint, as the recycled-plastic edging maker Plastic Forests suggests, and measure along it. A tape measure run around a curve by eye is always short. Add 5 % for cuts, or 10 % for a bed with many curves. Leave out any side that runs along a fence, wall or path.
Worked example: an 8 × 4 m vegetable bed edged all round is 2 × (8 + 4) = 24 m. With 5 % that is 25.2 m, so 25.2 ÷ 2.44 = 10.3, and you buy 11 steel lengths. At three stakes a length that is 33 stakes, plus 11 connectors, because a closed loop joins back on itself.
Edging materials compared
| Material | Piece | Fixings | Curves |
|---|---|---|---|
| Steel, FormBoss type | 2.44 m lengths | 3 stakes a length (every 813 mm), 4 for retaining or steps; a connector at each join | Bends to curves |
| Steel, EverEdge type | 1 m lengths, 75–150 mm high | Six spikes built into each length; lengths clip together | Bends to almost any shape |
| Plastic | Rolls, commonly 10 m | Pegs every 0.5–2 m, depending on soil, curves and height | Flexible; no tight corners |
| Treated pine | 4.8 m boards, 25 × 75 mm | A stake every 1–1.5 m; buy H4 for in-ground use | Gentle curves only |
| Bricks | 230 × 110 × 76 mm | 4.2 per metre end to end, 8.3 per metre laid across, with 10 mm joints | Follows curves with wedge-shaped joints |
| Concrete strip | Poured in place | Formwork, then about 110 bags of 20 kg per m³ | Any shape |
The steel figures come from the makers. FormBoss recommends three stakes per 2.44 m length for general use, one in the centre and one about 400 mm from each connection. It recommends four stakes per length for a retaining edge or steps. EverEdge lengths are 1.6 mm steel with six spikes pressed from the same piece. For plastic edging, Plastic Forests says to bury at least half its height, to let it stand no more than 15 mm above the lawn so the mower clears it, and to cut it into 3–10 m lengths overlapped by at least 50 mm, so it can expand in the sun without buckling. The Melbourne supplier Soilworx stocks treated pine edging in 4.8 m boards and recommends a stake every 1–1.5 m.
Mowing strips and runner grasses
Couch and kikuyu spread by runners on the surface and underground stems below it. University of California IPM describes kikuyu invading flower beds and ground covers until it chokes them out. No edging stops runners completely, because they eventually creep over the top. A deep, continuous edge slows the underground stems, and a flush strip lets you trim the rest.
A mowing strip is a band of bricks or concrete set flush with the lawn, wide enough for the mower wheel to run along, so the edge is cut as you mow. Bricks laid across the line give a strip about 230 mm wide, and bricks end to end about 110 mm. For a concrete strip, the calculator works out the volume and the bags. The concrete calculator compares bags with ready-mix, which only pays off for long strips. Choosing a lawn? The lawn grass types guide compares how far each grass runs.
Putting it in
- Mark the line with a rope, hose or marking paint, and keep curves gentle for plastic and pine.
- Cut a trench with a spade held vertical, so one side of the trench is a straight wall to set the edging against.
- Set the height. Along a lawn, keep the top low enough for the mower to pass over it. Plastic Forests suggests no more than 15 mm above the lawn.
- Fix it with the stakes or pegs as above. Use extra in sandy soil, on curves and anywhere the edge holds back soil.
- Backfill both sides, firm the soil and water it in to settle it.
Edging questions
How much edging do I need for a garden bed?
The length of every side you want edged, plus 5 % for cuts, or 10 % if the bed has many curves. A 4 × 2 m bed edged all round is 12 m, or 12.6 m with 5 %.
How many stakes does steel edging need?
FormBoss recommends three stakes per 2.44 m length, about every 813 mm, and four per length (every 610 mm) where the edge holds back soil or forms steps. Some other brands, such as EverEdge, have spikes built into each length, so no stakes are needed.
How many pegs does plastic edging need?
Plastic Forests gives a range of one peg every 50–200 cm, or none at all in firm ground with the edging well buried. You need more pegs in sandy soil, on curves and where the edging stands high. One a metre is a safe plan.
How many bricks do I need per metre of edging?
With standard 230 × 110 × 76 mm bricks and 10 mm joints: about 4.2 per metre laid end to end, and 8.3 per metre laid across the line. Add a few for cuts and breakages.
Sources and method
- FormBoss, Staking the edging (2.44 m lengths, 3 or 4 stakes per length) and Connecting the lengths.
- EverEdge Australia, steel garden edging: 1 m lengths, 1.6 mm steel, 75–150 mm heights, six built-in spikes.
- Plastic Forests, GreenMongrel garden edging installation instructions: burial depth, mower clearance, pegs every 50–200 cm, expansion joints.
- Soilworx, The complete guide to timber garden edging (November 2025): 4.8 m boards, H4 treatment, a stake every 1–1.5 m.
- Standard Australian brick of 230 × 110 × 76 mm with a 10 mm joint.
- University of California IPM, Kikuyugrass: spread by stems rooting at the nodes and invasion of beds.
Written by DueRiva · Last reviewed 24 September 2026 · Report an error