Onions (bulbing) planting calendar for USDA Zone 8b

Charleston SC, Savannah, Mobile, Austin, Jacksonville. Average last spring frost March 15, first fall frost November 15 — a 245-day frost-free season.

Zone fit: excellent
Onions (bulbing) is well suited to Zone 8b. Standard planting dates work with minor adjustments for microclimates.

Key dates

Start seeds indoors
December 28 – January 11
Transplant outdoors
January 25 – February 15
Expected first harvest
May 12 – June 9

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 8b

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 8b

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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