When to Plant Onions in New Jersey
The backbone of the kitchen garden. Choose short-day, intermediate, or long-day varieties based on your latitude.
The Short Answer
New Jersey Frost Dates
Your planting dates depend on which part of New Jersey you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern New Jersey | 6a, 6b | Apr 20 - May 5 | Oct 5 - Oct 20 |
| Central New Jersey | 6b, 7a | Apr 10 - Apr 25 | Oct 15 - Nov 1 |
| Southern New Jersey | 7a, 7b | Apr 1 - Apr 15 | Oct 20 - Nov 5 |
Onions Planting Schedule for New Jersey
Northern New Jersey (Zones 6a, 6b)
Average last frost: Apr 20 - May 5 · Average first frost: Oct 5 - Oct 20
Central New Jersey (Zones 6b, 7a)
Average last frost: Apr 10 - Apr 25 · Average first frost: Oct 15 - Nov 1
Southern New Jersey (Zones 7a, 7b)
Average last frost: Apr 1 - Apr 15 · Average first frost: Oct 20 - Nov 5
Growing Onions in New Jersey
Onions in New Jersey's Climate
Long-day onions are your type. Plant sets or transplants as soon as ground can be worked in spring. For the largest bulbs, start from seed indoors 10-12 weeks before last frost. Your June day length (15+ hours) triggers proper bulbing. Cure in a warm, dry location for 2-3 weeks before storage.
Soil Considerations for New Jersey
Sandy soils in Pine Barrens. Clay in north. Acidic in south. Rich loam in central agricultural areas. The Garden State for good reason. Loose, well-drained soil is especially important for onions since the edible portion grows underground. If your soil is heavy clay, consider raised beds.
New Jersey Climate & Growing Season
Moderate climate with maritime influence. Good growing season. Four seasons. Excellent for a wide range of crops. Onions can handle frost well, which is an advantage in New Jersey's climate. You can push planting dates earlier in spring and extend into fall.
Growing season length varies across New Jersey: Northern New Jersey (6a, 6b) has a last frost around Apr 20 - May 5, while Southern New Jersey (7a, 7b) sees frost end around Apr 1 - Apr 15. This difference matters for onions — but onions handle frost well, so the timing difference is less critical.
Growing Tips
Day length triggers bulbing. Northern gardeners need long-day varieties. Southern gardeners need short-day varieties.
Companion Planting
Plant onions alongside these companions for better growth:
Keep onions away from:
The Bottom Line
Last reviewed: March 29, 2026