Growing profiles
Choose how this crop will be grown. Dimensions, spacing and timing belong to the selected profile—not to the species as a single universal value.
Bulb onion
Mature bulb onion; propagation pathway does not change the mature profile.
- Biological height
- 30–60 cm (12–24 in) Source
- Mature canopy
- 10–20 cm (4–8 in) Source
- Plant spacing
- 5–10 cm (2–4 in) Source
- Row spacing
- 30–45 cm (12–18 in) Source
- Layout
- parallel rows · open ground Source
- Support
- Usually unnecessary
- Container
- At least 3 L (0.8 US gal) · 3 plant Source
- Best germination temperature
- 18 °C (64 °F) Source
Climate-relative calendar
Planning estimates become local dates after the gardener supplies frost dates and current conditions. Harvest and crop-removal dates are estimates: actual crop condition takes priority.
Plant Bulb onion42 days before last spring frost to 14 days before last spring frost SourceSourceRecommended: Soil temperature at least 2 °C (36 °F) for 3 consecutive days. Source
Thin Bulb onion seedlings21 days after plant bulb onion to 35 days after plant bulb onion Source
Begin harvesting Bulb onion100 days after sowing to 120 days after sowing Source
Finish harvesting Bulb onion14 days after first harvest to 30 days after first harvest
Remove Bulb onion cropthe expected end of harvest to 7 days after the expected end of harvest
Agronomy release agronomy-2026-07-11-r1 · reviewed 2026-07-11 by Gardeningist agronomic research synthesis. Each fact links to its supporting source.