How many plants fit in a bed?
It depends on how you lay them out as much as on the plant. The same 4 × 8 ft bed holds 36 heads of lettuce in conventional rows, 128 by the square-foot method, and 45 on an intensive grid — all at sensible spacings, because "rows" leave walking room the other two methods don't. The calculator shows all three for whatever you're planting; which one is right depends on whether you'll reach in from the sides (a bed) or walk between rows (a field).
- Rows — plants every x inches along rows y inches apart. Plants per row = length ÷ in-row spacing; rows = width ÷ row spacing. The packet's numbers; built for hoeing between rows.
- Square-foot — the bed is a grid of 1 × 1 ft squares and each square holds 1, 4, 9 or 16 plants (12, 6, 4 or 3 in apart) depending on the crop; big plants get several squares. Simple to lay out with string.
- Intensive grid — every plant at the in-row spacing in every direction, staggered (hexagonal) when that fits more. The most plants per square foot; the hardest to weed.
Spacing chart: how far apart to plant vegetables
| Crop | In row | Between rows | Per sq ft | In a 8 × 4 bed: rows / SFG / intensive |
|---|---|---|---|---|
| Tomato (staked) | 24 in | 36 in | 1 | 4 / 32 / 8 |
| Pepper | 18 in | 24 in | 1 | 10 / 32 / 10 |
| Eggplant | 24 in | 30 in | 1 | 4 / 32 / 8 |
| Broccoli / cauliflower | 18 in | 30 in | 1 | 5 / 32 / 10 |
| Cabbage | 18 in | 30 in | 1 | 5 / 32 / 10 |
| Kale / collards | 12 in | 24 in | 1 | 16 / 32 / 32 |
| Lettuce (heads) | 10 in | 12 in | 4 | 36 / 128 / 45 |
| Spinach | 4 in | 12 in | 9 | 96 / 288 / 306 |
| Swiss chard | 8 in | 18 in | 4 | 24 / 128 / 72 |
| Beet | 4 in | 12 in | 9 | 96 / 288 / 306 |
| Carrot | 3 in | 12 in | 16 | 128 / 512 / 567 |
| Radish | 2 in | 6 in | 16 | 384 / 512 / 1283 |
| Onion (bulbing) | 4 in | 12 in | 9 | 96 / 288 / 306 |
| Garlic | 6 in | 12 in | 4 | 64 / 128 / 140 |
| Bean, bush | 4 in | 18 in | 9 | 48 / 288 / 306 |
| Bean, pole (trellised) | 6 in | 30 in | 8 | 16 / 256 / 140 |
| Pea (trellised) | 3 in | 24 in | 8 | 64 / 256 / 567 |
| Sweet corn — Plant in blocks, not a single row, for pollination. | 10 in | 30 in | 4 | 9 / 128 / 45 |
| Cucumber (trellised) | 12 in | 48 in | 2 | 8 / 64 / 32 |
| Summer squash / zucchini — One plant per 3 × 3 ft. | 24 in | 36 in | 1 per 9 sq | 4 / 3 / 8 |
| Winter squash / pumpkin — Vines sprawl; give it the edge of the bed. | 36 in | 60 in | 1 per 9 sq | 0 / 3 / 2 |
| Melon | 24 in | 60 in | 1 per 4 sq | 0 / 8 / 8 |
| Potato | 12 in | 30 in | 1 | 8 / 32 / 32 |
| Strawberry | 12 in | 18 in | 1 | 16 / 32 / 32 |
| Basil | 10 in | 12 in | 4 | 36 / 128 / 45 |
| Marigold (bedding) | 8 in | 10 in | 4 | 48 / 128 / 72 |
Conventional spacings are midpoints of seed-packet and extension ranges; square-foot figures from the Square Foot Gardening Foundation chart. Counts computed by the engine for a 8 × 4 ft bed.
Staggering plants into triangles packs about 15% more into a large area — a 10 × 10 ft bed at 12 in spacing holds 105 plants staggered versus 100 in a square grid. But a 4 ft wide bed only has room for four rows either way, and the offset rows each lose a plant at the end; in a 4 × 8 the square grid wins. The calculator checks both and reports whichever is more, so you don't have to remember which.
Why spacing matters — and which way to err
Spacing sets how much light, water and root room each plant gets. Too tight and you get smaller yields per plant, more disease (no airflow) and more work thinning; too loose and you grow weeds in the gaps. For leaf crops you eat young — lettuce, spinach, radish — tight intensive spacing works because you harvest before they crowd. For fruiting crops — tomatoes, squash, peppers — err toward the packet's full spacing; a tomato at 18 in instead of 24 doesn't give you 33% more tomatoes, it gives you the same tomatoes and blight. And anything that vines needs either a trellis (then it takes the small spacing) or the edge of the bed and the lawn beyond.
From plants to seeds and transplants
The count above is plants at final spacing. Direct-sown crops are seeded two or three times as thick and thinned; transplants are bought or started at the final count plus a few spares. A seed-starting date calculator that works back from your frost date is next on this site's list.
Sources: Square Foot Gardening Foundation, Plant Spacing Chart; University of Maryland Extension, Vegetable Planting Calendar and Spacing; Oregon State Extension, Growing Your Own; Johnny's Selected Seeds planting guides. Triangular packing factor √3⁄2 from geometry.