Why spacing matters
Plants set too close compete for light, water and nutrients, and stay damp, which invites disease. Set too far apart, they waste bed space and leave room for weeds. The right spacing comes from the mature size of each plant, usually printed on the seed packet or plant tag. This calculator turns that spacing into a plant count for your bed.
How the count works
- Square grid: plants per row = length ÷ spacing, rows = width ÷ spacing, both rounded down
- Staggered (triangular): rows are 0.866 × spacing apart, and every other row is offset by half a spacing
- Each plant sits half a spacing from the edge of the bed
- Plants to buy = plants that fit × (1 + spare margin)
Worked example
A classic 4 × 8 ft raised bed planted at 12 inches:
- Plants per row: 96 in ÷ 12 = 8.
- Rows: 48 in ÷ 12 = 4.
- Total: 32 plants, one per square foot.
- With a 10% margin, buy 36.
In a staggered pattern, this small bed holds 30 plants rather than 32, because offset rows lose a plant at the edge. On wide beds, staggering fits about 15% more plants.
Typical spacing for vegetables
| Crop | Spacing in the row | Plants per sq ft (square grid) |
|---|---|---|
| Carrots, radishes | 2 to 3 in | 16 |
| Onions, beets | 3 to 4 in | 9 |
| Lettuce, spinach | 6 to 10 in | 4 |
| Bush beans | 4 to 6 in | 9 |
| Broccoli, cabbage | 18 in | 1 per 2 sq ft |
| Peppers, eggplant | 18 in | 1 per 2 sq ft |
| Tomatoes, staked | 18 to 24 in | 1 per 2 to 4 sq ft |
| Squash, zucchini | 24 to 36 in | 1 per 4 to 9 sq ft |
These are typical values; varieties differ, and the seed packet has the final word.
Square-foot gardening
A popular method for small beds divides each square foot into a grid of 1, 4, 9 or 16 plants depending on the crop’s size. It uses the same arithmetic as a 12, 6, 4 or 3 inch spacing, and avoids paths between rows.
Tips
- Row spacing versus plant spacing: traditional row gardens leave wider gaps between rows for walking. In beds you never step on, use the in-row spacing in both directions.
- Thin seedlings to the final spacing once they have true leaves, rather than sowing exactly.
- Interplant: fast crops like radishes can fill the gaps between slow ones like peppers and be harvested before the space is needed.
- Ornamental beds: for ground covers, a staggered pattern gives a more natural, faster-filling look.