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.
- Typical mature height
- 12–24 in (30–60 cm) Editorial synthesisbasis
- Mature canopy
- 4–8 in (10–20 cm) Editorial synthesisbasis
- Plant spacing
- 2–4 in (5–10 cm) Editorial synthesisbasis
- Row spacing
- 12–18 in (30–45 cm) Editorial synthesisbasis
- Planting arrangement
- parallel rows · open ground Editorial synthesisbasis
- Support
- Usually unnecessary
- Optional container
- At least 0.8 US gal (3 L) · 3 plant Editorial synthesisbasis
- Best germination range
- 36–86 °F (2–30 °C) Editorial synthesisbasis
Climate-relative calendar
Frost and transplant rules become local dates when climate data is available. Cultivar maturity and crop condition are never replaced by a fabricated date.
Plant Bulb onion42 days before last spring frost to 14 days before last spring frost Direct sourceEditorial synthesisbasisRecommended: Soil temperature at least 36 °F (2 °C) for 3 consecutive days. Editorial synthesisbasis
Thin Bulb onion seedlings21 days after plant bulb onion to 35 days after plant bulb onion Direct source
Begin harvesting Bulb onion100 days after sowing to 120 days after sowing Planning estimatebasis
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. Direct-source links indicate close source support; synthesis and planning estimates are labeled separately.