Plant spacing calculator

How to measure for planting

For a hedge, measure the full length of the run along the line where the plants will go. The calculator puts a plant at each end and spaces the rest evenly between them. If the hedge turns a corner, add the lengths of the two sides together and enter the total, so the corner plant is only counted once.

For a bed or border, measure its length and width. The calculator treats it as a rectangle, so for an irregular bed measure the rectangle it fits best, or work it out in parts. Bulbs work the same way: measure the patch you want to fill, not the whole border.

Then set the spacing: the distance from the centre of one plant to the centre of the next. Plant labels and nursery catalogues usually give it, and the hedge presets use the RHS spacings. Lengths can be in metres or in feet and inches; switch the units at the top.

Hedge spacings and bulbs per m²

The hedge spacings are the RHS’s figures for plants in a single row, except box, which has our own default (see below). The bulb numbers are a UK bulb supplier’s figures for a full display. Where the RHS gives a range, the button applies the closer spacing, which fills in sooner; widen it towards the top of the range for fewer plants and a slower hedge.

The bulb numbers are for a solid patch of flowers. For bulbs dotted through a lawn or among other plants, use fewer. The RHS’s one firm rule is to leave at least twice the bulb’s own width between bulbs.

How many hedge plants per metre?

The number of hedge plants per metre depends on the spacing and on whether you plant one row or two. In a single row, divide 100 cm by the spacing: plants 50 cm apart is two a metre. A whole hedge needs one plant more than that sum, because there is a plant at each end, and the calculator counts it for you.

The RHS spacings give a hedge that fills in at a natural pace. Nurseries often plant closer to get a dense hedge sooner: Ashridge Nurseries suggests three plants a metre for most hedges. Both work: closer planting means more plants and a quicker screen. If your nursery gives a number per metre, divide 100 cm by it and type that in as the spacing.

Laurel plants per metre

Laurel is a big, fast evergreen, and the RHS spaces it 60 cm apart, which is fewer than two plants a metre in a single row. For a quicker screen, plant two staggered rows at the same spacing.

Beech plants per metre

The RHS spaces beech 45–60 cm apart. At the closer spacing that is a little over two plants a metre in one row, and two staggered rows give a thicker hedge from the start. The worked example below is a beech hedge in two rows.

Lavender plants per metre

Lavender makes a low, informal hedge planted 30–37.5 cm apart, so you need about three plants a metre in a single row. Compact varieties suit the closer spacing, bigger ones the wider.

Box plants per metre

Box is planted much closer than other hedges, and how close depends on what you want: the closer end of 15–30 cm for a low edging round a bed, the wider end for a taller box hedge. Ashridge Nurseries plants box at five a metre, and the RHS spaces a full box hedge wider still. The Box hedge button starts in the middle of the range, which is our own default, so change the spacing to suit the hedge you have in mind.

One row or two staggered rows?

The RHS suggests a double, staggered row where you want a thick or wide hedge. The second row starts half a spacing along, so each plant sits opposite a gap in the first row. Choose Two staggered rows and the calculator adds the second row, which roughly doubles the plants. Keep the rows close together; your nursery can advise on the gap for the plants you buy.

Plants per m² in a bed or border

For ground cover, perennials or bedding, choose A bed or border and enter the length, the width and the spacing from the plant label. In a square grid each plant has a square the size of the spacing, so at 50 cm apart you get four plants per m². In a staggered layout each row shifts half a space along, which fits about 15% more plants at the same spacing and leaves fewer bare gaps.

The calculator assumes the outer plants sit roughly half a spacing in from the edge of the bed. If you want to leave a wider strip clear along a lawn or path, measure the bed to that line instead.

Bulbs per square metre

Choose Bulbs, measure the patch and pick a bulb above. The presets use a UK bulb supplier’s figures for a full display, from 25 per m² for large alliums to 150 per m² for crocuses, with tulips and daffodils at 60 per m². For other bulbs, type the number per m² from the pack.

Plant them in loose groups rather than lines, and scatter them more thinly where they come up through grass or other plants.

Worked example: a beech hedge in two rows

Here is the full calculation for a beech hedge along a boundary, planted at the RHS spacing in two staggered rows with no spares. Every line comes from the same code that runs the calculator above, so the figures always match.

1. First row 12 m ÷ 45 cm, rounded down, + 1 (a plant at each end) = 27 plants
2. Second row, staggered starts 22.5 cm in, same spacing = 27 plants
3. Plus spares 54 + 0%, rounded up = 54 plants

On the list:

• 54hedge plantsBeech hedge

Notice that the second row starts half a spacing in from the end, so its plants sit opposite the gaps in the first, and yet both rows still reach the far end. For a long hedge it is worth adding a few spares: a plant that fails in the first year is easier to replace from your own spares than to match later.

UK hedge plant and bulb sizes

Hedge plants are sold bare-root, root-balled or in pots, in a range of heights. The size you buy changes how soon the hedge looks finished, not how far apart the plants go: the spacing depends on how big the hedge will grow. Bulbs are sold by number in packs and nets, so the count from the calculator is what you order.

Common mistakes when spacing plants

• Dividing the length by the spacing and stopping there. A hedge needs one more plant than that, because there is a plant at each end.
• Measuring between the edges of plants. Spacing runs from the centre of one plant to the centre of the next.
• Copying a nursery’s per-metre figure without the spacing. Nurseries often plant closer than the RHS, so decide which you are following before you order.
• Planting a bed on a square grid out of habit. A staggered layout leaves fewer bare gaps at the same spacing, though it needs a few more plants.
• Ordering no spares. A long hedge often loses a plant or two. Add a little in Spares so the gaps can be filled from the same batch.

What else you'll need

• Compost or soil improver dug into the planting strip: the compost calculator works out the bags.
• Bark mulch round new plants to hold in moisture and keep weeds down: use the bark calculator.
• Topsoil for a new bed or a raised border: the topsoil calculator covers that.
• A garden line and a cane cut to the spacing, so every plant goes in the same distance from the last.
• Stakes and ties for taller hedge plants in exposed spots.

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