SPACE & PLANT
How plant spacing and edge margins change your layout
Use final plant spacing, row spacing and a stated edge margin to count planting positions in a rectangular bed.
Use three distances, not one
Plant spacing is the centre-to-centre distance between neighbouring plants in one row. Row spacing is the distance between neighbouring rows. Edge margin is the minimum distance from the inside wall to the centre of a plant.
Use the final spacing for your variety and growing method. A seed packet can list a close sowing distance and a different final spacing after thinning. The spacing planner uses the numbers you choose; it does not assign one universal distance to a crop.
A 4 × 8-foot example
Take a 96 × 48-inch interior, 12 inches between plants, 12 inches between rows and at least 6 inches to every edge. Eight plants fit along the length and four rows fit across the width: 32 planting positions. This is a layout example, not a recommended number of any particular vegetable.
Along length: floor((96 − 2 × 6) ÷ 12) + 1 = 8
Why the grid is centred
A bed may not divide evenly by the selected spacing. The planner keeps the requested spacing and splits any remaining room between the two ends. Its reported actual margins may therefore be larger than your minimum.
Rotating a rectangular bed while retaining different plant and row spacing can change the count. Use the Rotate button to compare the two orientations. A bed too small for both edge margins has zero positions.
Compare both orientations with uneven spacing
For an 8 × 4-foot interior, set 18 inches between plants, 24 inches between rows and a 6-inch minimum edge. The planner fits two rows of five positions, or 10 in total. Rotate the bed to 4 × 8 feet while keeping those spacing values, and it fits four rows of three, or 12 positions. These are geometric examples, not recommended spacings for a crop.
The original five positions span four gaps: 4 × 18 = 72 inches. The remaining 24 inches of the 96-inch bed length are split between the two ends, so each end margin is 12 inches. The tool keeps the requested plant spacing instead of stretching the gaps.
| Measurement or result | Original | Rotated |
|---|---|---|
| Length × width | 8 × 4 ft | 4 × 8 ft |
| Plant / row spacing | 18 / 24 in | 18 / 24 in |
| Minimum edge | 6 in | 6 in |
| Rows × plants per row | 2 × 5 | 4 × 3 |
| Total positions | 10 | 12 |
| Actual end / side margin | 12 / 12 in | 6 / 12 in |
If the result is zero, check the edges first
A 10-inch-wide strip cannot hold a planting centre that must remain at least 6 inches from both sides. Reducing the spacing between plants will not solve that problem: the two edge margins already require 12 inches. Check the plantable width and the intended margin before changing other inputs.
The imperial tool takes bed length and width in feet, but plant, row and edge spacing in inches. A 96-inch length should be entered as 8 feet. In Centimetres mode all five distances use centimetres. Changing units converts your current distances; it does not choose new spacing for a crop.
What a dot on the plan means
Each marker is one planting centre. It is not a drawing of mature foliage or roots. The tool does not calculate shade, companion relationships, crop rotation, access paths, trellises or yield. Reserve room for those features before entering your plantable rectangle.
Use the spacing for plants you intend to keep after thinning. The resulting position count is not a count of seeds to sow. Check the packet for sowing and thinning instructions for your variety.
Before choosing the layout with the most dots, check whether you can reach the middle from the accessible sides without stepping into the bed. University of Minnesota Extension discusses width and access when planning raised beds. If you need an access strip, leave it out of the plantable rectangle. For a mixed bed, plan one rectangular section at a time.