How much landscape edging do you need?

How much landscape edging do I need?

Measure along each bed or path edge you want to border — a flexible tape or a garden hose laid along a curve works well — and add about 5% for overlaps and trimming. A 60 ft bed edge plus 5% is 63 feet — four 20 ft kits, or a 50 ft and a 20 ft kit.

How do I measure a curved bed?

Lay a garden hose or string along the curve, mark it where the edge ends, then straighten it and measure. Enter each separate bed or path as its own run so the spikes are counted per piece.

How many stakes or spikes does edging need?

Westlake Dimex asks for a spike at least every 40 inches for its EasyFlex edging, so a 20 ft run takes 7 and a 60 ft run 19. Kits include spikes, but tight curves and soft soil need more — count them against the result.

Plastic, metal or stone edging?

Plastic no-dig edging is the cheapest and easiest to shape around curves. Steel and aluminum edging stays straighter and lasts longer but costs more. Paver or stone edging is sold by the piece — use the paver calculator for it.

How deep should edging go?

Deep enough to stop grass roots — usually most of the edging's height in the soil, with about half an inch above ground so a mower wheel can ride over it. Follow the maker's instructions for the product you buy.

Why does the spike count change when I enter the runs separately?

Because each piece of edging needs a spike at both ends as well as in between. Entering 20, 14, 36 ft separately gives 7 + 6 + 12 = 25 spikes, while one 70 ft run would need 22. Counting per run gives the number you actually have to buy.

How do I edge around a tree or a round bed?

Measure the circumference: for a circle of radius r it is 2πr. A bed 6 ft across has a radius of 3 ft and an edge of about 18.8 ft. Flexible plastic edging is made to bend around curves; rigid steel and paver edging need a tighter fit or cuts. Add the overlap at the joint where the two ends meet.

What is counted

The calculator adds the lengths you enter, adds the waste allowance for overlaps and cuts, and divides by the length of a piece or kit to give the number to buy. Spikes are counted for each run: one at least every 40 inches along it and one at the end, following the spacing the maker of one common product specifies. Landscape edging is usually sold in kits of 20 feet or more, so the number of kits is rounded up.

Worked example: three runs of edging

A bed has edges of 20, 14, 36 feet, 70 feet in all. With 5% extra for overlaps and trimming that is 73.5 feet, which takes 4 kits of 20 ft. Counted per run, the spikes are 7 + 6 + 12 = 25. Measuring a curved edge with a garden hose and straightening it gives the length to enter.

Common mistakes

Measuring a curved edge in a straight line understates the length; follow the curve with a hose or string. Another is forgetting the spikes for corners and soft ground, where a spike every 40 inches may not hold. Edging that sits too low lets grass roots creep under it, and edging set too high is a trip hazard and catches the mower. The depth and spacing in the maker's instructions for the product you buy overrule the planning figures on this page.

Sources: spike spacing — Westlake Dimex, EasyFlex no-dig edging installation instructions (a spike at least every 40 inches); the circumference formula 2πr is standard geometry. Related: paver calculator, mulch calculator, fence calculator and topsoil calculator.