Using SowWindow
Beds, containers and spacing
The spacing calculator places plant centers inside a shape you define. The diagram, count, and coordinate list describe the same positions. It is an explicit layout model, so you can inspect how the answer was obtained rather than relying on an area estimate.
Reviewed Oct 27, 2026
Enter the shape and units
Choose a rectangle for a bed with a usable length and width, or a circle for a container described by its inside diameter. Select the units before entering dimensions. Measure growing space inside the boundary; the tool does not subtract a wall or walkway you have not represented.
Enter positive plant spacing and row spacing. Plant spacing separates centers along a row; row spacing separates neighboring row centers. The edge allowance sets how far every center must stay from the boundary. Custom values are choices, not source-endorsed defaults.
Read a rectangular layout
The first center in each direction is placed at the edge allowance. Further centers are added at the selected spacing until the next center would cross the opposite allowed boundary. Each directional count is floor((dimension − 2 × margin) / spacing) + 1, provided the usable span is not negative.
For a 300 × 120 cm bed with 30 cm plant and row spacing and a 15 cm margin, the counts are ten columns and four rows. The total is 40 centers. At these dimensions, the lengthwise coordinates run from 15 to 285 cm and the widthwise coordinates from 15 to 105 cm.
Read a circular layout
The circular model uses a regular grid aligned to the container center. It retains a point only when the distance from that center is no greater than the container radius minus the edge allowance. This is a reproducible grid arrangement, not a claim of the most densely possible packing.
For a 120 cm diameter, 30 cm plant and row spacing, and a 15 cm allowance, the permitted center radius is 45 cm. The nine grid points with each coordinate at −30, 0, or 30 cm fit inside it. Inspect the coordinate list if the dots are hard to distinguish.
Resolve a no-fit result
If the shape is too small for the chosen boundary and spacing rules, the result can be zero positions. The tool must not draw plants outside the allowed area to make the layout look complete.
Check the units first, then dimensions, margin, and spacing. Increase the usable space or deliberately choose another arrangement. Do not reduce crop spacing solely to force a higher number without checking the applicable growing guidance.
Save and use the layout
Read both the count and the source conditions before adding the layout to your plan. A geometric fit does not assess roots, support, sunlight, access, or the crop’s growing conditions. Keep any excluded area or special arrangement in the notes.
Download SVG for the diagram and measurements, or use the coordinate table to mark centers. Carry the target plant count into the seed-quantity calculator when starting seed. Changing the layout later requires a new estimate; an older downloaded diagram will not update itself.