When to plant onions (bulbing) in USDA Zone 7b

Plan your onions (bulbing) planting around local frost risk and soil temperature, then work backward from the harvest week your buyers need. The calendar below is a starting point, not a field-level weather forecast.

Raleigh, Greensboro, Richmond, Knoxville, Memphis. Average last spring frost April 8, first fall frost October 22 — a 197-day frost-free season.

Zone fit: excellent
Onions (bulbing) is well suited to Zone 7b. Standard planting dates work with minor adjustments for microclimates.

Key dates

Start seeds indoors
January 21 – February 4
Transplant outdoors
February 18 – March 11
Expected first harvest
June 5 – July 3

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 7b

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 7b

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.