Seed Starting Calculator
Onions.
Onions uses a reviewed indoor transplant start profile instead of the former universal six-week default. The local frost date remains editable because cultivar, soil, hardening and microclimate can move the plan.
Onions profile
Onions uses a reviewed indoor transplant start profile instead of the former universal six-week default. The local frost date remains editable because cultivar, soil, hardening and microclimate can move the plan.
- Reference method: indoor transplant start; published lead-time reference: 9–12 weeks.
- Day-length type and whether starting from seed, sets or transplants materially change the plan.
Work backward from your local last-frost date by the crop's reviewed indoor-start lead time.
Context matters.
- Cultivar, transplant tolerance, germination temperature, hardening and local microclimates can shift the planting window.
Sources & scope
The calculation guide and this source trail show what the result means, where the rule came from and when it was last reviewed. This is source-and-calculation QA, not a claim of medical, legal, tax or other professional review; time-sensitive decisions still belong with the linked authority.