Onions (bulbing) planting calendar for USDA Zone 6b

Boone NC, northern VA, central KY, southern IN. Average last spring frost April 24, first fall frost October 8 — a 167-day frost-free season.

Zone fit: challenging
Short-day onion varieties bulb best in Zones 7 and warmer; northern growers should choose intermediate-day types instead.

Key dates

Start seeds indoors
February 6 – February 20
Transplant outdoors
March 6 – March 27
Expected first harvest
June 21 – July 19

Windows are calculated from your zone's average frost dates. Adjust ±1 week for microclimates, elevation, and your own frost records.

Spacing and soil

Plant spacing
4″
Row spacing
12″
Seed depth
0.25″
Soil temperature
50–75°F
Frost tolerance
hardy
Days to harvest
100 days

Grower notes for Zone 6b

Southeast growers must plant short-day varieties. Long-day types will make tops but never bulb below 36° latitude.

Plant near: carrots, beets, lettuce

Keep away from: beans, peas

Other alliums for Zone 6b

Same crop, other zones

Track your own plantings

BAU Farm Intelligence turns these windows into per-field tasks — indoor seed-start reminders, transplant dates, harvest projections — using your farm's actual frost history.

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