North Carolina planting calendar

When to plant onions in North Carolina — sow, transplant & harvest dates

North Carolina is mostly USDA zone 7b (range 5b-8b). Dates below are derived from onions's frost tolerance and North Carolina's frost window — not generic national averages.

Onions planting timetable for North Carolina

Stage	When in North Carolina	Anchor
Start seeds indoors	late January (January 25)	10 weeks before the last frost (early April)
Transplant outside	early March (March 8)	28 days before the last frost (early April)
First harvest (estimate)	late June (June 26)	~110 days from transplant

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why North Carolina's climate shifts the onions dates

North Carolina's last spring frost averages early April and first fall frost late October, which sets the whole planting clock. North Carolina runs from cool mountains through the Piedmont to a warm coastal plain — one of the widest east-coast zone spans. Sow early — onions bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Onions are day-length sensitive: long-day varieties (zones 1–6) begin bulbing when days exceed 14 hours, short-day types (zones 7–10) bulb at 10–12 hours, and intermediate-day varieties span zones 5–6. Start seeds indoors 10–12 weeks before the last spring frost and transplant out 4–6 weeks before it — young onion seedlings tolerate frost down to about -6 °C once hardened off. In zones 8–10 a second planting from sets in autumn is common, overwintering for an early-summer harvest.

Frost-risk note

Don't plant before early April — a hard freeze can still set young plants back. In the high Blue Ridge near Mount Mitchell (zone 5b) the safe date runs a week or two later.

Regional variation within North Carolina

the high Blue Ridge near Mount Mitchell (zone 5b) runs roughly 1-2 weeks behind the state average; the southern coast around Wilmington (zone 8b) can plant 1-2 weeks earlier.

Charlotte — USDA zone 8a
Raleigh — USDA zone 8a
Greensboro — USDA zone 7b
Asheville — USDA zone 7a
Wilmington — USDA zone 8b

What else to plant in North Carolina around then

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: 10-35 °C (50-95 °F).
Spacing: 4-6 inches (10-15 cm) between plants.
Days to harvest: ~110 days from planting out.

Frequently asked questions

When is the best time to plant onions in North Carolina?

In North Carolina (mostly USDA zone 7b), sow onions indoors around late January, transplant outdoors early March (before the last frost, early April), and harvest from late June. Onions are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

What USDA zone is North Carolina?

Most of North Carolina sits in USDA hardiness zone 7b, with the state spanning roughly 5b-8b from the high Blue Ridge near Mount Mitchell (zone 5b) to the southern coast around Wilmington (zone 8b). The last spring frost averages early April and the first fall frost late October.

Can you grow onions in North Carolina?

Yes. North Carolina's dominant zone 7b supports onions — the key is timing. Onions are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

Does the planting date change across North Carolina?

the high Blue Ridge near Mount Mitchell (zone 5b) runs roughly 1-2 weeks behind the state average; the southern coast around Wilmington (zone 8b) can plant 1-2 weeks earlier.

What else can I plant in North Carolina around the same time?

The same early window suits peas, lettuce, spinach, and onion sets.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.