When to Plant Onions in Nebraska
The backbone of the kitchen garden. Choose short-day, intermediate, or long-day varieties based on your latitude.
The Short Answer
Nebraska Frost Dates
Your planting dates depend on which part of Nebraska you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern/Western Nebraska | 4a, 4b | May 5 - May 20 | Sep 20 - Oct 5 |
| Eastern Nebraska | 5a, 5b | Apr 25 - May 10 | Oct 1 - Oct 15 |
Onions Planting Schedule for Nebraska
Northern/Western Nebraska (Zones 4a, 4b)
Average last frost: May 5 - May 20 · Average first frost: Sep 20 - Oct 5
Eastern Nebraska (Zones 5a, 5b)
Average last frost: Apr 25 - May 10 · Average first frost: Oct 1 - Oct 15
Growing Onions in Nebraska
Onions in Nebraska's Climate
You're in long-day onion territory — plant varieties that bulb when days exceed 14-16 hours. This means Copra, Walla Walla, and Yellow Globe Danvers. Plant sets or transplants from mid-April. The critical distinction: short-day onions from southern catalogs will NOT form bulbs in your zone because your long summer days trigger bulbing too early, before the plant is large enough.
Soil Considerations for Nebraska
Rich prairie soils in east. Sandy soils in Sandhills region. Loess deposits along Missouri River. Loose, well-drained soil is especially important for onions since the edible portion grows underground. If your soil is heavy clay, consider raised beds.
Nebraska Climate & Growing Season
Continental climate. Hot summers, cold winters. Adequate growing season in east. Drier in west — irrigation may be needed. Onions can handle frost well, which is an advantage in Nebraska's climate. You can push planting dates earlier in spring and extend into fall.
Growing season length varies across Nebraska: Northern/Western Nebraska (4a, 4b) has a last frost around May 5 - May 20, while Eastern Nebraska (5a, 5b) sees frost end around Apr 25 - May 10. 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