Filling a bed comes down to the spacing you plant at: the closer the spacing, the more plants — and the count climbs with the square of it, so small changes make a big difference. Here is how to work out the number, and whether to grid or stagger the rows.
The formula
Plants per square foot = 1 ÷ spacing² (spacing in feet), then multiply by the bed area. At 12 in (30 cm) spacing that is about 1 plant per sq ft (roughly 11 per m²), so a 65 sq ft (6 m²) bed takes about 67 plants in square rows — or about 77 staggered.
Square or staggered?
Staggered (triangular) rows place each plant in the gap of the row before, giving even coverage and about 15% more plants per square foot — the standard for groundcovers and mass planting. Square grids suit formal layouts and anything you need to walk or cultivate between.
Plant Spacing Calculator
Enter the bed area and spacing for the plant count — square or staggered triangular layout.
What spacing to use
| Plant | Spacing |
|---|---|
| Groundcovers | 8–12 in (20–30 cm) |
| Perennials, small shrubs | 12–20 in (30–50 cm) |
| Larger shrubs | 3 ft+ (1 m+) |
Space to the plant’s mature spread, not its nursery-pot size — the label’s spread figure is the spacing. Planting tighter looks full sooner but costs more and crowds later.
Measure center to center
Spacing is stem to stem, not the gap between leaves. Keep half a spacing back from the bed edge so mature plants don’t spill over paths and lawn — the per-square-foot figure already averages that out for larger beds.
Saving on plant numbers
Stretch the spacing 20% and mulch the gaps — most groundcovers close the difference within a season or two. Buying smaller pot sizes at the correct spacing usually beats buying big plants tight: the small ones establish faster and cost a fraction.