Gardening
Plant Spacing Calculator
Enter bed size and spacing between plants to see a grid count.
How many plants for a bed?
Crowded plants compete for light, water and air flow; sparse planting looks thin and invites weeds. This calculator estimates how many plants fit a bed from bed length and width plus the recommended spacing on the seed packet or nursery label. Square-grid and triangular (offset) patterns use space differently — offset rows often fit slightly more plants in the same rectangle. Paths, existing shrubs and shed overhangs should be excluded from the plantable area. Companion planting still needs each species’ spacing respected. Soil volume for raised beds sits on garden soil. Successional sowing may use the same spacing chart more than once in a season. Guidance for planning purchases — not agronomy advice for commercial crops. Check mature width, not the plug size in the tray, or your summer bed will become a jungle. Watering and feeding plans scale with plant count, so the number you order should match what you can actually look after.
Worked example
A bed 3 m × 1.2 m = 3.6 m². At 30 cm spacing on a square grid you fit roughly (300/30) × (120/30) = 10 × 4 = 40 planting points. With a 10% gap for edges and stakes, buy about 36 plants. Halving spacing to 15 cm for salad leaves roughly quadruples the count — only if the variety allows it.
Limits and assumptions
Assumes a clear rectangle and uniform spacing. Triangular layouts need their own row offset. Does not account for germination losses — sow or buy a few extras.
Frequently asked questions
Should I use the spacing on the packet?
Yes as a starting point — it reflects the plant’s mature width better than guesswork.
Square or triangular spacing?
Triangular (offset) rows can fit more plants; square grids are easier to mark out.
Do I include paths in the bed size?
No — measure only the planted area.
What about germination failure?
Buy or sow a small surplus, especially with older seed.
Can I mix tall and short crops?
Yes, but give each its own spacing and think about shade from the taller plants.