Plant PulseBig onion
Allium cepa L.
Big onion. Sourced figures stay next to their citation. Planting windows are listed for locations that have one. Unsourced fields say coming soon.
Unverified — based on Field Crops – Big onion – Sinhala, Department of Agriculture Sri Lanka, Sinhala page, accessed 2026-10-20: https://doa.gov.lk/field-crops-bigonion-si/; confirm for your microclimate.
Spacing
- In-row spacing
- 10 cm
- Between-row spacing
- 10 cm
Other sourced figures
- Soil pH
- 6.5–7.8
From farmer field experience
Based on hands-on growing experience from Sri Lankan farmers. Not yet verified against official sources.
- Nursery days: 28–35 days
- Nursery days for seedlings. Bulblets are also used.
- Farmer field notenoted Oct 2026
- Days to first harvest: 85–100 days
- Days after transplanting. The Sinhala page gives variety lines from 75–85 through 100–110 and does not store one crop-level pair.
- Farmer field notenoted Oct 2026
- Harvest window: 15–20 days
- How long the bulbs stay at a useful size.
- Farmer field notenoted Oct 2026
Market months
Prices vary by week, market, and year. This is not financial advice.
Based on hands-on growing experience from Sri Lankan farmers. Not yet verified against official sources.
Higher prices: November–May
The local crop is grown in Yala. Imports cover the rest of the year.
Farmer field notenoted Oct 2026
Lower prices: August–October
The local crop is grown in Yala. Imports cover the rest of the year.
Farmer field notenoted Oct 2026
Planting windows
Colombo — Low Country Wet Zone
Official planting windows: coming soon.
From farmer field experience
Based on hands-on growing experience from Sri Lankan farmers. Not yet verified against official sources.
Not recommended in this zone
Direct sow or transplant
Farmer field notenoted Oct 2026
Not recommended in this zone. Humidity. This is reviewed field experience, not an official Department of Agriculture prohibition.
Unverified — based on Farmer field experience, noted 2026-10-23; confirm for your microclimate.
No when-to-plant page for a zone where this crop is not recommended.
Mid Country
Official planting windows: coming soon.
From farmer field experience
Based on hands-on growing experience from Sri Lankan farmers. Not yet verified against official sources.
May–June
Transplant
Farmer field experience. Using 85–100 stored days. Plant in May, first harvest about 85–100 days later (around August). Plant in Jun, first harvest around September. Calculated from the stored day count and the planting month. It is not a separate harvest calendar.
Farmer field notenoted Oct 2026
Mid Country, May–June, Yala, on rain-sheltered beds.
Unverified — based on Farmer field experience, noted 2026-10-23; confirm for your microclimate.
Up Country Wet Zone
Official planting windows: coming soon.
From farmer field experience
Based on hands-on growing experience from Sri Lankan farmers. Not yet verified against official sources.
Not recommended in this zone
Direct sow or transplant
Farmer field notenoted Oct 2026
Not recommended in this zone. Not a useful big-onion climate in this note. This is reviewed field experience, not an official Department of Agriculture prohibition.
Unverified — based on Farmer field experience, noted 2026-10-23; confirm for your microclimate.
No when-to-plant page for a zone where this crop is not recommended.
Low Country Dry Zone
Yala: April–May
Transplant
Farmer field experience. Using 85–100 stored days. Plant in Apr, first harvest about 85–100 days later (around July). Plant in May, first harvest around August. Calculated from the stored day count and the planting month. It is not a separate harvest calendar.
Sinhala big-onion page: seedlings or dry bulbs, Yala from mid-April to mid-May. The grid marks April and May. Cultivation is mainly in the dry zone.
Unverified — based on Field Crops – Big onion – Sinhala, Department of Agriculture Sri Lanka, accessed 2026-10-20: https://doa.gov.lk/field-crops-bigonion-si/; confirm for your microclimate.
Maha: December
Transplant
Farmer field experience. Using 85–100 stored days. Plant in Dec, first harvest about 85–100 days later (around March). Calculated from the stored day count and the planting month. It is not a separate harvest calendar.
Sinhala big-onion page: if cultivated in Maha, during December.
Unverified — based on Field Crops – Big onion – Sinhala, Department of Agriculture Sri Lanka, accessed 2026-10-20: https://doa.gov.lk/field-crops-bigonion-si/; confirm for your microclimate.
From farmer field experience
Based on hands-on growing experience from Sri Lankan farmers. Not yet verified against official sources.
March–May
Transplant
Farmer field experience. Using 85–100 stored days. Plant in Mar, first harvest about 85–100 days later (around June). Plant in May, first harvest around August. Calculated from the stored day count and the planting month. It is not a separate harvest calendar.
Farmer field notenoted Oct 2026
Low Country Dry Zone nursery, mid-March to May. The grid marks March, April, and May.
Unverified — based on Farmer field experience, noted 2026-10-23; confirm for your microclimate.
May–July
Transplant
Farmer field experience. Using 85–100 stored days. Plant in May, first harvest about 85–100 days later (around August). Plant in Jul, first harvest around October. Calculated from the stored day count and the planting month. It is not a separate harvest calendar.
Farmer field notenoted Oct 2026
Low Country Dry Zone transplant, May–July, Yala.
Unverified — based on Farmer field experience, noted 2026-10-23; confirm for your microclimate.