How Much Garden Edging Do I Need?

Count the sides first

A 20 × 6 ft bed:

Sides edged	Linear feet
All four	52
Three (one against a wall)	46
Two (a corner bed)	26
One (front edge only)	20

Most beds don't need all four. One running along a house wall, a fence, or a paved path with its own edge needs only the exposed sides — typically three, two for a corner bed, and sometimes just the front.

Working this out before ordering routinely cuts a quarter or a third off the material — and it takes one look at the bed rather than any arithmetic.

The calculator shows the full perimeter beside your figure, and what you saved by not edging every side. That comparison is there deliberately: the saving is invisible unless you see both numbers together, and it is almost always the largest one available on the page.

Measure curves with a rope

Edging follows a curve. A tape measures the straight line across it.

The curve is always longer, and the error grows with how pronounced it is. Estimating a curved front from the straight distance under-orders every time — and it's the single most common way an edging order comes up short.

Lay a hose along the line you actually want, then measure the hose. Difference between one trip to the yard and two.

Why the waste allowance is low

5% for a single bed with straight runs. 10% if you have several separate beds.

Offcuts are usually reusable here, unlike most materials — the piece left at the end of one run generally starts the next. That's a genuinely different situation from tile or flooring, where an offcut is frequently useless.

The 10% figure applies when each bed begins with a fresh piece and the leftovers are too short to start another.

Stakes are what people under-buy

More than come in the box. This is the recurring complaint about edging kits.

Roughly one every 3 feet, closer on curves where the material is under tension trying to spring back straight, plus one at each corner.

Under-staked edging looks perfect on the day it goes in and lifts out of the ground over the first winter as the soil freezes and thaws. That's the commonest way an edging job fails — and stakes are the cheapest part of it.

Depth decides whether it works at all

Edging that sits proud of the soil looks tidy and stops absolutely nothing. Grass simply grows over and through it.

To work as a barrier against creeping grass it has to be set deep enough to intercept the runners travelling sideways through the top few inches of soil. Follow the manufacturer's stated depth rather than however deep the trench happened to end up.

Digging that trench properly is most of the labour on this job, and most of whether it works.

The free alternative, which is genuinely good

A cut edge — a clean vertical slice made with a half-moon edger, no material whatsoever.

A great many gardens use nothing else. It costs zero, looks excellent, and its only downside is needing redoing once or twice a year.

Installed edging buys that maintenance back and gives a harder barrier against creeping grass.

It's a real trade rather than an upgrade, and it's worth making deliberately before spending anything. If you've already decided, that's what the calculator is for.

Pieces, and what a roll actually gives you

Edging is sold two ways and they behave differently.

Rolls of flexible plastic or metal cut to any length, so a roll's worth of material is genuinely usable end to end. Rigid sections come in fixed lengths, and a run that needs 14 ft of 8 ft sections needs two — with 2 ft left over that may or may not start the next bed.

The calculator rounds pieces up either way, which is right, but the leftover means something different in each case. For rolls it's a genuine surplus. For rigid sections it's an offcut whose usefulness depends on whether your next run is longer than it.

Worth checking before ordering: whether your system needs corner pieces or connectors. Some do, they're rarely included in the linear-foot price, and discovering it halfway through stops the job dead.

Before you dig

• Check for utilities before trenching anywhere near the house
• Plan the turf removal and where the spoil goes — that's most of the work
• Set the depth from the manufacturer's figure, not from however deep the trench ended up

Print the take-off sheet — it has a row per bed, so several beds get measured separately instead of estimated together.