Plant Onions in Zone 7b

Seed-starting, transplant & harvest dates for USDA Zone 7b

Start indoors

Jan 23

Transplant

Mar 20

Harvest (~100d)

Jun 28

Zone 7b averages 212 frost-free days, running from a last spring frost around April 3 to a first fall frost around November 1. Onions needs roughly 100 days from planting out to first harvest, so it uses about 47 percent of that window. Onions is a hardy crop, which is what decides where in the window it belongs.

Because onions needs a head start, sow seed indoors around Jan 23, about 10 weeks ahead of the Zone 7b last frost. Transplants go out around Mar 20. Starting earlier than that in Zone 7b usually backfires: plants outgrow their cells and stall when they finally hit cold soil.

Planting onions for a fall harvest in Zone 7b

Yes. Plant onions between September 20 and October 11 in Zone 7b, roughly 6 to 3 weeks before the average first frost, so it roots before the ground freezes.

Short-day onion sets planted in fall overwinter in zone 7 and warmer and bulb up months ahead of a spring planting.

Plant from

Sep 20

Plant by

Oct 11

Overwinters, harvest in spring

Spring

Fall dates are counted backward from the Zone 7b average first frost, not forward from a sowing date. See the fall planting calendar by zone for the full method.

Spring vs fall onions in Zone 7b

Planting	Sow or start	In the ground	Harvest
Spring	Jan 23	Mar 20	Jun 28
Fall	by Oct 11	Oct 11	Next spring

Last spring frost

Apr 3

First fall frost

Nov 1

Growing season

212 days

Onions in nearby zones

Onions in Zone 7a (colder) Onions in Zone 8a (warmer) Full Onions grow guide Zone 7b planting calendar

Other crops in Zone 7b

Tomatoes in Zone 7b Peppers in Zone 7b Cucumbers in Zone 7b Lettuce in Zone 7b Zucchini in Zone 7b Carrots in Zone 7b Beans (bush) in Zone 7b Peas in Zone 7b Broccoli in Zone 7b Spinach in Zone 7b Kale in Zone 7b Garlic in Zone 7b Potatoes in Zone 7b Squash (winter) in Zone 7b Corn in Zone 7b Radishes in Zone 7b Beets in Zone 7b Eggplant in Zone 7b Basil in Zone 7b Cilantro in Zone 7b Parsley in Zone 7b Pumpkins in Zone 7b Sunflowers in Zone 7b

Frequently asked questions

When should I start onions in Zone 7b?

Start onions seeds indoors around Jan 23 (Zone 7b).

Can I direct sow onions in Zone 7b?

Onions is best started indoors and transplanted in Zone 7b rather than direct sown.

Can I plant onions in the fall in Zone 7b?