Spring Onion
Green Onion, Scallion, Bunching Onion, Welsh Onion, Japanese Bunching Onion
Direct sow in early spring, 4–6 weeks before last frost. Can also be planted in late summer for fall harvest. Succession sow every 3 weeks for continuous supply. Pull when whites are pencil-thick. Very frost-tolerant; often overwinters in mild climates. Can be grown from the root ends of store-bought bunches placed in water.
- Spacing
- 8 cm
When to plant spring onion
Sow outdoors 4–6 weeks before your last spring frost.
Dashed line: typical last spring frost in zone 7 (Apr 5). Zone dates are averages; most of the UK is zone 8–9, central Europe 6–7 and the Baltics and Scandinavia 4–6. In the app, Tomatograph uses your garden's own frost dates.
How to grow spring onion
- 1
Sow
Sow thinly in rows 4–6 weeks before the last frost. Spring onions are very frost-tolerant.
- 2
Keep sowing
Sow a short row every three weeks for a steady supply, and again in late summer for autumn.
- 3
Grow on
Keep weeds down and water in dry spells.
- 4
Harvest
Pull when the white stems are about pencil-thick. You can also regrow the root ends of shop-bought bunches in water.
Growing conditions
Light
Full sun
Water
Medium water
Temperature
4–27 °C
Frost tolerance
Frost-hardy — tolerates frost
Days to maturity
60–80 days
Ideal soil pH
7–7.5
How Tomatograph watches your spring onion
Tomatograph checks your local forecast every morning and only speaks up when one of these applies to your garden.
- First frost within 14 daysReminder to mulch the roots before winter.
- 3 days at 35 °C or aboveHeat-wave alert while plants are flowering or fruiting: shade and water early.
- Humidity above 80% for 48 hoursCheck for downy mildew, which thrives in those conditions.
- Within a week of maturityHarvest-window reminder based on when you planted.
Spring Onion questions
- When should I plant spring onion?
- Sow outdoors 4–6 weeks before your last spring frost.
- How far apart should I plant spring onion?
- Allow 8 cm between plants.
- What grows well with spring onion?
- Good neighbours include carrot, beet, tomato, lettuce.
Growing guide written by Tomatograph. Planting figures from OpenFarm crops rescue (CC0 1.0). Zone frost dates are averages from openplantdb (CC0 1.0).