Spacing
How far apart to plant onions, shallots and garlic
The short answer
Onion sets go 10 to 15cm apart in rows 20 to 30cm apart. Shallot sets need 15 to 20cm in rows 25 to 30cm apart. Garlic cloves go 15cm apart in rows 30cm apart, with the tip 2.5cm below the surface. Wider spacing gives bigger bulbs; closer spacing gives more, smaller ones.
The onion family is where spacing changes the crop most visibly. The same row can give you a few big onions or a lot of small ones, and RHS says so plainly.
The spacing
- Onions (from seed): RHS spaces rows 20 to 30cm apart for sets and direct-sown seed, and 25 to 30cm for module-raised transplants.
How many fit in a bed
Worked out with the same method as the plant spacing calculator, for three common bed sizes.
| Crop | 2.4 × 1.2m bed | 1.2 × 1.2m bed | 3 × 1.2m bed |
|---|---|---|---|
| Onions (sets) | 64 to 144 | 32 to 72 | 80 to 180 |
| Onions (from seed) | 96 to 144 | 48 to 72 | 120 to 180 |
| Shallots (sets) | 48 to 72 | 24 to 32 | 60 to 96 |
| Shallots (from seed) | 108 | 48 | 144 |
| Garlic | 64 | 32 | 80 |
| Leeks | 48 to 64 | 24 to 32 | 60 to 80 |
Why this spacing
- Wider spacing, larger bulbs. RHS spaces onion sets 10 to 15cm apart and notes the wider end gives larger bulbs.(RHS)
- Closer spacing, more but smaller bulbs. For shallots, closer spacing gives more bulbs and a heavier overall crop, but smaller individual bulbs.(RHS, RHS)
- Seed-sown onions are thinned twice: first to 5cm, later to 10cm apart.(RHS)
- Module-raised onions go about 10cm apart, or 15cm for large onions, in rows 25 to 30cm apart.(RHS)
How deep
- Onion sets: 2cm deep in drills.(RHS)
- Shallot sets: just the tip showing at the surface.(RHS)
- Garlic: the tip 2.5cm below the soil. In light soil, deeper planting can give larger bulbs; don’t plant deeply in heavy soil.(RHS)
- Garlic keeps its spacing in pots and raised beds: 15cm apart in the ground, raised beds or pots.(RHS)
Put your beds on a plan, free
Add each bed with its size and what is growing in it. Vercro draws the plan to scale, keeps the record, and shows what each empty bed could take next.
Keep going
Where this comes from
Every spacing figure comes from the crop's RHS grow-your-own page, or Garden Organic where RHS gives none, linked beside the figure. The Vercro app's catalogue holds no spacing, so none of these numbers come from it. Reviewed 19 September 2026.
- Onions: grow your own, Royal Horticultural Society. Read 19 September 2026.
- How to grow shallots, Royal Horticultural Society. Read 19 September 2026.
- Garlic: grow your own, Royal Horticultural Society. Read 19 September 2026.
- How to grow Leeks, Royal Horticultural Society. Read 19 September 2026.