Root vegetable
Can you grow Onion on a balcony?
Allium cepa
Yes — grows well in pots
Onion (Allium cepa) grows well on a balcony in a pot of at least 40 litres (about 45 cm deep). It needs full sun — around 6+ hours of direct sun a day. Spring-planted sets crop July-October; autumn-planted sets from June-July.. All figures below are sourced from RHS and the Old Farmer's Almanac.
Sun
☀️ Full sun (6+ h)
Min. pot
40 L · 45 cm
Water
Medium
Difficulty
Easy
Hardiness
Annual
Container fit
Good
Sow
Sow indoors mid-winter to early spring, or plant sets 2cm deep in early to mid-spring (autumn sets for an earlier crop).
Harvest
Spring-planted sets crop July-October; autumn-planted sets from June-July.
Good companions: Carrots, beets, cabbage, lettuce and strawberries; scent repels carrot fly and aphids
Avoid nearby: Beans, peas and Mediterranean herbs like sage
Balcony tip: Use a container at least 45cm (18in) wide and deep with soil-based compost; stop watering once bulbs have swollen in mid-summer.
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More root vegetables for balconies
Häufige Fragen
What size pot does Onion need?
Onion needs a container of at least 40 litres, roughly 45 cm deep. Bigger pots dry out more slowly and give better yields on a balcony.
How much sun does Onion need on a balcony?
Onion wants full sun — about 6+ hours of direct sun daily. Match it to your balcony's aspect before buying seed.
When do you sow Onion?
Sow indoors mid-winter to early spring, or plant sets 2cm deep in early to mid-spring (autumn sets for an earlier crop).. Timing shifts with your climate/USDA zone — the linked sources give the detail.
Sources & date
- RHS: Onion
- Old Farmer's Almanac: Onion
- Data as of: 2026-07-10
- Container sizes and timings are guidance — adjust to your climate/USDA zone and balcony aspect.