Getting spacing right
Spacing is the one decision you cannot revisit once seedlings are in. Too tight and every plant underperforms; too loose and you have paid for bed space you are not using. The numbers below are mature spreads, not seedling sizes.
Spacing by crop
| Crop | Spacing | Per 4 × 8 bed |
|---|
Counts are for a square grid with half-spacing edge margins, as the calculator above works it out.
Square grid or offset rows?
A square grid puts plants on a simple lattice: easy to mark with string, easy to hoe down straight lines. Offset rows stagger every second row by half a spacing, which lets you pull the rows closer — to 0.866 of the spacing — while keeping every plant the same distance from its neighbours. That is where the extra 15% comes from.
Offset works best for low crops you harvest by hand: lettuce, onions, beetroot. For anything you need to walk between, or that gets staked, the tidy grid is worth more than the extra plants.
When to ignore the recommended spacing
- Cut-and-come-again leaves. Salad you harvest young can go far tighter than the packet says — you are picking before the plants ever need full spread.
- Dry sites and poor soil. Spacing figures assume decent soil and regular water. Without both, widen them — the constraint is root volume, not leaf room.
- Anything prone to blight or mildew. Tomatoes, courgettes and squash want more air movement than the minimum spacing gives, especially in a humid summer.
- Climbing crops. Beans and peas grown up supports need spacing along the row only; the row gap is set by the frame, not the plant.
Three worked examples
A small herb bed, 2 × 2 ft, at 6-inch spacing
With 3-inch edge margins, a 6-inch grid gives 4 rows of 4 — 16 plants in 4 square feet, exactly the one-per-6-inch density square foot gardening uses for compact herbs like thyme or chives.
A 3 × 6 ft bed at 9-inch spacing, square grid
4 rows of 8 fit on a square grid — 32 plants, a common spacing for beets, bush beans and similar mid-sized crops.
A 4 × 6 ft bed at 9-inch spacing, square vs. offset
On a square grid this bed fits 5 rows for 40 plants. Switching to offset closes the row gap to 7.8 inches, which is enough to squeeze in a sixth row — 45 plants, a 12.5% gain. Offset only pays off when the tighter row gap crosses a whole extra row like this; on a bed just a foot narrower, the same switch can cost a plant instead of adding one, because the row count stays the same while alternating rows lose their outermost plant.
Square foot gardening vs. traditional row spacing
Traditional row spacing — the kind printed on most seed packets — leaves a walkway-width gap between rows so a hoe or a hose reel can pass through, then packs plants tightly within the row. It works well in open ground where soil is free and space isn't. Square foot gardening drops the walkways inside the bed entirely and spaces plants evenly in both directions, because in a raised bed you reach in from the edge rather than walking between rows. For the same footprint it typically fits noticeably more plants, at the cost of needing genuinely good soil to support that density — the packet spacing assumes native ground, not an intensive raised bed.
Still filling the bed? The Soil Calculator works out the volume it takes, and the Watering Schedule estimates what the finished planting will drink each week.