Quick planting window
| Start indoors | February to March |
|---|---|
| Transplant | April to May |
| Sow seeds | April to May |
| Estimated harvest | July to August |
| Risk | Medium risk |
Month calendar
Scan the year by month to see seed starting, sowing, transplanting, and harvest timing.
Onion is a reasonable spring choice for New Jersey if you adjust for your local microclimate.
Next: ZIP code personalization
This is a state-level planning window based on typical frost timing and crop rules. Use local Extension guidance or a ZIP code frost-date tool before planting.
Planning notes
Days to maturity
110
Covered states
New Jersey
Frost window
April to May / October to November
Northwest New Jersey is cooler than coastal and southern New Jersey.
Onion growing notes
The calendar window is only the first step. These growing details affect survival, plant vigor, and harvest quality.
Sun
Full sun.
Soil
Loose, fertile soil with good drainage.
Spacing
4-6 inches for bulbs.
Container
Use wide containers at least 8-10 inches deep.
Watering
Keep evenly moist during bulb formation.
Common mistake
Choosing the wrong day-length onion type.
Beginner tip
Use sets or transplants if seed timing feels too long.
Month window table
| Crop | Spring transplant / sow | Spring harvest | Fall transplant / sow | Fall harvest |
|---|---|---|---|---|
| Onion | April to May | July to August | July to August | October to November |
Sources and limits
This page uses New Jersey state-level frost windows, USDA zone ranges, and crop rules for planning. It does not replace local Extension or county-level guidance.
FAQ
When should I start onion seeds indoors in New Jersey?
For spring, the indoor seed-starting window is about February to March. Move later if your local frost date is later than the state average.
When should I transplant onion in New Jersey?
For spring, the transplant window is about April to May. Harden seedlings off before planting outside.
Can I sow onion outdoors in New Jersey?
Yes. The spring outdoor sowing window is about April to May, assuming soil and night temperatures are suitable.
When can I harvest onion in New Jersey?
Spring planting estimates a harvest around July to August; fall planting estimates about October to November. Variety and weather can shift this by several weeks.
Is onion risky in New Jersey?
Onion is a reasonable spring choice for New Jersey if you adjust for your local microclimate. For fall: Onion is a reasonable fall choice for New Jersey if you adjust for your local microclimate.
Do local differences inside New Jersey matter?
Northwest New Jersey is cooler than coastal and southern New Jersey. Treat this as a state-level starter window and confirm with a local Extension or frost-date tool before planting.
What growing details matter most for onion?
Full sun. Loose, fertile soil with good drainage. Common mistake: Choosing the wrong day-length onion type.
Is this ZIP-code accurate?
No. This page uses state-level windows; ZIP-code frost dates, USDA zone matching, and reminder calendars are planned for the next phase.