Garden & outdoors

Plant spacing calculator

Count plants in aligned rows with an explicit edge margin. Use equal spacing or set a different distance between rows, in inches or centimetres.

Your measurements

Change any value to calculate

Switch units without changing your quantities. The formula and worked example below keep their stated units.

The inside bed dimension running along each row of plants. The calculator does not rotate the layout automatically.

in

The inside bed dimension across the rows. Separate row spacing, when enabled, is applied in this direction.

in

Center-to-center distance between plants along the bed length. This also sets the distance between rows unless you enable different row spacing.

in

Minimum distance from a plant’s center to each bed edge. The last row can leave a larger margin when another full spacing will not fit.

in
Different spacing between rows OptionalUse different spacing between rows?: No — use the same spacing

These settings still apply when this section is closed.

Choose Yes when your crop guidance gives a different distance between rows. The rows remain aligned and equally separated; this does not create staggered or double-row groups.

Center-line distance from one aligned row to the next, across the bed width. Use crop and variety guidance; 18 inches is an editable example, not a recommendation.

in
Grid planting positions
40 plants
Along the length
10 positions
Across the width
4 positions
Spacing along each row
12 in
Spacing between rows
12 in

Displayed values are rounded. Whole packages and purchase lengths round up. See assumptions below.

Calculation details

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How to use this calculator

Use spacing guidance for your crop and variety. Bed length runs along each row; bed width runs across the rows. Enter the center-to-center distance between plants along a row and the minimum distance from a plant center to every bed edge. By default, rows have the same spacing. Open Different spacing between rows and choose Yes to enter another center-to-center row distance. Choose inches or centimetres with the measurement-system control. To compare the other orientation, swap the bed length and width yourself; the calculator does not rotate the layout automatically.

The formula

Plants along each row = max(0, round down((bed length − 2 × margin) ÷ spacing along the row) + 1). Rows across the bed = max(0, round down((bed width − 2 × margin) ÷ spacing between rows) + 1). Multiply these counts. A dimension smaller than twice the margin has zero positions. Unless different row spacing is enabled, the same spacing is used in both directions.

A worked example

A 120 × 48 inch bed with 12 inch spacing and a 6 inch margin has 10 positions along its length and 4 across its width: 40 plants total. Keeping those measurements but using 18 inches between rows gives 10 plants per row × 3 rows = 30. In centimetres, a 240 × 120 cm bed with 15 cm margins, 20 cm spacing along rows and 45 cm between rows gives 11 × 3 = 33 positions.

Assumptions & limitations

This is an aligned rectangular-grid count, not a planting recommendation. All rows use the same within-row spacing and every adjacent row uses the same row spacing. It does not model staggered plants, double-row groups, paths, mixed crops or plant spread. The same minimum edge margin applies in both directions; the final plant or row may leave more space at the opposite edge. A dimension exactly twice the margin admits one center. Example spacings are editable arithmetic examples, not universal crop recommendations. The RHS reference provides crop-specific spacing context, not an endorsement of this geometric model.

Common questions

Is the spacing between plant edges?

No. Within-row spacing is center to center between plants. Row spacing is center line to center line between adjacent aligned rows.

Which bed dimension runs along the rows?

Bed length. Bed width is the dimension across the rows. Swap length and width to compare a rotated layout while keeping your chosen plant and row spacings.

Can I use this for double or staggered rows?

No. It uses equally separated, aligned single rows. A double-row arrangement needs its smaller within-pair gap and larger between-pair gap represented separately.

Why can the result be zero?

The chosen margin may leave no valid planting position along one side. Check the measurements and appropriate crop guidance before changing the margin.

Supporting reference

The method above states this calculator’s assumptions. This reference provides related definitions and technical context.

RHS: broad bean single-row spacing (crop-specific context) ↗

Formula and worked example checked against automated test cases. About our methodology.

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