How the plant spacing calculator works
The two layouts
Square grid: plants in straight rows and columns. Plants per row = floor(bed length × 12 ÷ spacing) + 1; rows work the same across the width. It's tidy, easy to weed, and what most tags assume.
Triangular: each row offset half a spacing, like a stadium crowd. It fits about 15% more plants in the same bed and closes the canopy faster — the standard for groundcovers, mass plantings, and anyone who wants fewer visible weeds sooner.
Reading the tag correctly
Tag spacing means center-to-center at mature size — not the size of the plant in the pot. Annuals often crowd happily (a 10–12" tag spacing tolerates 8–10" for a fuller first season); shrubs and trees must not be crowded, because their mature size is structural. When a tag gives a range ("12–18 in"), the low end is fast-dense, the high end is low-maintenance.
Practical notes
- Buy 5–10% extra annuals to replace the inevitable causalities — pro landscapes budget a replacement rate.
- Edge rows sit half a spacing from the bed edge, which the calculator's count already reflects.
- Vegetable gardens: respect the tag. Crowded tomatoes and squash trade yield for disease.