Root Vegetable

When to Plant Onions in North Carolina

The backbone of the kitchen garden. Choose short-day, intermediate, or long-day varieties based on your latitude.

The Short Answer

North Carolina straddles the short-day/intermediate-day onion line, with the coastal plain suited to short-day types and the mountains suited to intermediate or long-day varieties. The Piedmont can go either way depending on elevation and microclimate.

North Carolina Frost Dates

Your planting dates depend on which part of North Carolina you're in. Here are the frost date ranges by region:

Region Zones Last Frost (Spring) First Frost (Fall)
Mountains 5b, 6a, 6b Apr 25 - May 15 Sep 25 - Oct 10
Piedmont 7a, 7b Apr 1 - Apr 15 Oct 20 - Nov 5
Coastal Plain 7b, 8a Mar 15 - Apr 1 Nov 1 - Nov 15

Onions Planting Schedule for North Carolina

Mountains (Zones 5b, 6a, 6b)

Average last frost: Apr 25 - May 15 · Average first frost: Sep 25 - Oct 10

Start Seeds Indoors
10 wks before frost
Transplant Outside
4 wks before frost
Direct Sow
4 wks before frost

Piedmont (Zones 7a, 7b)

Average last frost: Apr 1 - Apr 15 · Average first frost: Oct 20 - Nov 5

Start Seeds Indoors
10 wks before frost
Transplant Outside
4 wks before frost
Direct Sow
4 wks before frost

Coastal Plain (Zones 7b, 8a)

Average last frost: Mar 15 - Apr 1 · Average first frost: Nov 1 - Nov 15

Start Seeds Indoors
10 wks before frost
Transplant Outside
4 wks before frost
Direct Sow
4 wks before frost

Growing Onions in North Carolina

State-Specific Growing Tips

Coastal plain: plant short-day transplants from October-November. Piedmont: plant intermediate-day from November-January. Mountains: plant intermediate or long-day from February-March. NC State Extension provides a detailed onion day-length guide for the state's three regions — following the correct type for your location is the single most important decision.

Recommended Varieties for North Carolina

Short-day (coast): Granex, Texas 1015. Intermediate (Piedmont): Candy, Super Star. Long-day (mountains): Copra, Walla Walla. NC State variety trials include onion data.

Common Challenges in North Carolina

Thrips statewide. Botrytis in humid conditions. Pink root. Using the wrong day-length type is the most common failure — consult NC State's regional guide.

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:

Carrots Lettuce Beets Tomatoes

Keep onions away from:

Beans Peas

The Bottom Line

Onions can be grown successfully in North Carolina with proper attention to regional frost dates and local growing conditions. Timing varies across the state — Mountains gardeners work with a last frost around Apr 25 - May 15, while Coastal Plain sees frost end around Mar 15 - Apr 1. Choose varieties suited to your region, amend your soil based on its specific needs, and monitor for the pests and diseases most common in your area. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Onions Growing Guide National planting guide with all states North Carolina Planting Calendar All plants for North Carolina Onions in Alabama Alabama planting dates Onions in Alaska Alaska planting dates Onions in Arizona Arizona planting dates Onions in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

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