The nursery pot tells you what arrives; mature spread helps you plan what the bed becomes. Choose spacing after selecting the species and cultivar, not before.
Decide whether you want separate clumps or a connected planting
For a specimen effect, leave room to see the shape of each mature clump. For a repeated border or groundcover effect, use the plant's recommended spacing and allow for how it spreads. Clumping and running plants need different expectations and maintenance.
Use center-to-center measurements
A spacing of 18 inches means measuring from the center of one plant to the next. Mark those centers on the prepared bed before digging, then check the edges for clearance from paths and walls.
Estimate a rectangular grid
For an initial estimate, divide the planting area in square feet by spacing in feet squared. A 100-square-foot bed at 18-inch spacing gives 100 ÷ 1.5² = about 44 planting positions. At 24-inch spacing, the same calculation gives 25. These are planning estimates; irregular edges, setbacks and the actual row layout change the final count.
Do not solve every gap with tighter spacing
Young plants leave visible soil. Adding more plants can raise the initial cost and create later crowding. Compare the cost of additional plants with the appearance you want at maturity and the work you are willing to do if division or thinning becomes necessary.
Make the final layout specific
Write the selected cultivar, its mature width, proposed spacing and bed dimensions on one sheet. Browse small-garden options or use our project inquiry page for a larger planting. For screening, also read our privacy planting guide.
This worksheet is a layout calculation, not a species-specific spacing recommendation. Check the chosen plant's requirements before ordering.