When to plant onions in Hawaii
Hawaii spans USDA hardiness zones 10-13. Average last spring frost: no average frost in most of the state. This calendar gives you the indoor start, transplant, and direct-sow dates for Allium cepa.
Hawaii planting dates for onions
Dates for Hawaii vary significantly by region. Use the average frost date lookup for your specific ZIP code, then apply the standard offsets: start onions indoors 12 weeks before your last frost; transplant 2 weeks before last frost;
Why these dates
Onions are day-length sensitive. Long-day varieties for the North (above latitude 35), short-day varieties for the South (below 35), day-neutral varieties work anywhere.
The dates above are anchored to Hawaii's average last spring frost date of no-frost, with offsets standard across university Extension publications. For zone-specific local timing, use the frost date lookup tool with your ZIP code.
More on growing onions
The full growing guide for onions - varieties, soil, fertilization, pests, harvest, storage - is here: Onions growing guide.
More Hawaii planting information
- Full Hawaii planting calendar (all crops + ornamentals)
- Find your exact USDA zone by ZIP
- Look up your average frost dates
- Seed starting timeline calculator