Planting positions in a bed: worked spacing examples (UK)

If you already have spacing from a seed packet or another source you trust, the planting planner can count a grid. It has no verified crop spacings and cannot say what a plant needs. For a wider bed-and-path drawing, see the polytunnel size guide.

Understand the two axes

“Length” and “width” are the two dimensions entered into the planner. They do not have to mean the long and short sides: if you turn the bed plan, swap the two dimension values.

For any entered orientation, the planner counts row lines across the width axis. Those rows run parallel to the length axis, where the plant positions are counted. Convert bed dimensions from metres to centimetres before dividing; for example, 2.4 m is 240 cm.

• rows = floor(width in cm ÷ row spacing in cm)
• positions along each row = floor(length in cm ÷ plant spacing in cm)
• total positions = rows × positions per row

Each division is rounded down to a whole number. The calculation uses a half-spacing allowance at both edges. If an axis is shorter than its corresponding spacing, that axis has zero positions. This is the planner's grid convention, not crop-clearance advice.

When the planner displays the result as a bed diagram, it centres the counted grid in a rectangle drawn to the entered proportions. That display helps show the count and the unused space; it does not change the arithmetic or recommend where a crop should go.

Exact fit: 3 m by 1.2 m

Enter a length of 3 m, width of 1.2 m, row spacing of 30 cm and plant spacing of 30 cm. The width is 120 cm, so 120 ÷ 30 = 4 rows. The length is 300 cm, so 300 ÷ 30 = 10 positions along each row. The total is 4 × 10 = 40 positions.

Both divisions are exact, so there is no remainder on either axis.

Remainder: 2.4 m by 1 m

Enter a length of 2.4 m and width of 1 m, with row spacing of 35 cm and plant spacing of 40 cm. Across the width, 100 ÷ 35 = 2 whole rows, with 30 cm left over. Along the length, 240 ÷ 40 = 6 positions. The result is 2 × 6 = 12 positions.

For a centred display, the unused 30 cm on the width axis is split evenly: 15 cm is added at each edge beyond the half-spacing allowance. This describes how the pictured grid is placed; the count itself comes from rounding down.

When one axis has no positions

For a bed with width 80 cm and length 240 cm, use row spacing of 90 cm and plant spacing of 40 cm. The width division gives 80 ÷ 90 = 0 whole rows. Six positions would fit along the length (240 ÷ 40 = 6), but with no rows the total is 0. This result follows from these inputs and the planner's grid convention; it does not assess whether another spacing is suitable.

Compare a quarter turn

Use the same rectangle, 2.5 m by 1.2 m, with row spacing 35 cm and plant spacing 50 cm.

With width = 1.2 m and length = 2.5 m, the planner counts 120 ÷ 35 = 3 rows and 250 ÷ 50 = 5 positions per row: 15 positions.

Turn the plan and swap the entered dimensions: width = 2.5 m, length = 1.2 m. Now it counts 250 ÷ 35 = 7 rows and 120 ÷ 50 = 2 positions per row: 14 positions. In both cases, row spacing stays attached to the row count and plant spacing to the positions along each row.

The larger count does not establish which orientation is better for a crop or for access. Before using a grid, confirm that the bed dimensions are right and choose row and plant spacing from a source appropriate to your plan. The planner turns those inputs into a count and a centred display, not horticultural advice.