Planting positions and center-to-center span
The main total multiplies positions per bed by the whole bed count. Unshifted and half-spacing shifted rows are counted separately, respecting the same margins. The alternate-orientation result swaps the row direction without changing the entered spacings. Center spans exclude plant width.
To estimate the fill beneath this layout, use the Raised Bed Soil Calculator with the bed’s inside dimensions.
The formula
The usable centre span is the bed dimension after both edge margins are removed. Each complete spacing interval connects two positions, so one is added after rounding down. Any unused remainder can be distributed between the two edges to centre the grid. Staggering shifts alternate rows by half the in-row spacing. Row spacing stays exactly what you enter; this does not automatically produce equilateral triangles. Bed lengths entered in meters or feet convert to centimeters while spacing and clearance remain in centimeters.
Worked example
A 300 cm by 120 cm bed with 15 cm clearance at every edge has usable centre spans of 270 cm and 90 cm. At 30 cm spacing both ways, it fits ten plants per row and four rows, giving forty positions.
How to use this calculator
- Choose aligned or staggered rows and their direction. Enter bed length/width in centimeters, meters or feet.
- Enter within-row and between-row spacing in centimeters, plus the minimum edge clearance in centimeters.
- Optionally enter a whole number of identical beds. Compare positions per bed, the opposite orientation and the total; use the breakdown for center spans.
Spacing is a planting decision
Use spacing appropriate to the crop or plant variety and its intended mature size. This calculator counts positions after that decision; it does not determine a horticulturally suitable distance. Separate row spacing can reserve room for access or accommodate crops whose recommended row and within-row distances differ.
Why area divided by spacing can differ
An area-density estimate ignores the boundary of each side. This form counts positions within the entered margins. Aligned rows use the same count in every row; staggered rows shift alternate rows by half the within-row spacing. Internal paths, circular beds and mixed planting plans are not modeled.
Compare row direction before repeating the layout
In the default 300 cm by 120 cm bed with 15 cm margins and 30 cm spacing both ways, aligned rows contain 40 positions. Offsetting alternate rows by 15 cm leaves ten positions in unshifted rows and nine in shifted rows, for 38 positions. Turning the staggered rows to run along the bed width produces 35 positions under the same margins.
Two identical beds repeat the selected layout twice; they do not merge their boundaries into one larger bed. Half-spacing staggered rows are not necessarily an equilateral triangular grid because the between-row spacing remains your entered value. The tool chooses no crop-specific planting distance.
Assumptions & limitations
What this calculation assumes
- Centers use aligned rows or alternating half-spacing shifted rows with the entered row spacing.
- The same minimum edge clearance applies on all four sides.
What to keep in mind
- Counts planting locations, not germination, survival, or harvest yield.
Common questions
Why is there one extra position after dividing?
Spacing counts gaps. Three gaps connect four plant centres, which is why the formula adds one.
What happens if only one centre fits?
A single position has zero centre-to-centre span. It can be centred within the bed while respecting the edge clearance.
Does staggered mode automatically choose triangular row spacing?
No. It offsets alternate rows by half the in-row spacing but retains your entered distance between rows. A triangular horticultural layout needs an appropriate independently chosen row spacing.
Sources & further reading
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