When to Plant Onions in Oklahoma
The backbone of the kitchen garden. Choose short-day, intermediate, or long-day varieties based on your latitude.
The Short Answer
Oklahoma Frost Dates
Your planting dates depend on which part of Oklahoma you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Oklahoma | 6b, 7a | Apr 5 - Apr 20 | Oct 15 - Nov 1 |
| Central Oklahoma | 7a, 7b | Mar 25 - Apr 10 | Oct 25 - Nov 10 |
| Southern Oklahoma | 7b | Mar 15 - Apr 1 | Nov 1 - Nov 15 |
Onions Planting Schedule for Oklahoma
Northern Oklahoma (Zones 6b, 7a)
Average last frost: Apr 5 - Apr 20 · Average first frost: Oct 15 - Nov 1
Central Oklahoma (Zones 7a, 7b)
Average last frost: Mar 25 - Apr 10 · Average first frost: Oct 25 - Nov 10
Southern Oklahoma (Zones 7b)
Average last frost: Mar 15 - Apr 1 · Average first frost: Nov 1 - Nov 15
Growing Onions in Oklahoma
Onions in Oklahoma's Climate
You straddle the day-length divide. Southern areas need short-day varieties (plant in fall for spring harvest), northern areas can use intermediate-day types. The single most important decision for onion success in your zone is choosing the right day-length type — the wrong one produces scallions instead of bulbs regardless of how well you grow them.
Soil Considerations for Oklahoma
Red clay soils common. Alkaline in west. Rich prairie soils in east. Wind erosion in western panhandle. Loose, well-drained soil is especially important for onions since the edible portion grows underground. If your soil is heavy clay, consider raised beds.
Oklahoma Climate & Growing Season
Hot summers. Severe thunderstorms and tornado risk. Good growing season length. Windy — windbreaks help gardens. Onions can handle frost well, which is an advantage in Oklahoma's climate. You can push planting dates earlier in spring and extend into fall.
Growing season length varies across Oklahoma: Northern Oklahoma (6b, 7a) has a last frost around Apr 5 - Apr 20, while Southern Oklahoma (7b) sees frost end around Mar 15 - Apr 1. 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