Plant Onions in Zone 6a

Seed-starting, transplant & harvest dates for USDA Zone 6a

Start indoors

Feb 9

Transplant

Apr 6

Harvest (~100d)

Jul 15

Zone 6a averages 176 frost-free days, running from a last spring frost around April 20 to a first fall frost around October 13. Onions needs roughly 100 days from planting out to first harvest, so it uses about 57 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 Feb 9, about 10 weeks ahead of the Zone 6a last frost. Transplants go out around Apr 6. Starting earlier than that in Zone 6a usually backfires: plants outgrow their cells and stall when they finally hit cold soil.

Planting onions for a fall harvest in Zone 6a

Yes. Plant onions between September 1 and September 22 in Zone 6a, 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 1

Plant by

Sep 22

Overwinters, harvest in spring

Spring

Fall dates are counted backward from the Zone 6a 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 6a

Planting	Sow or start	In the ground	Harvest
Spring	Feb 9	Apr 6	Jul 15
Fall	by Sep 22	Sep 22	Next spring

Last spring frost

Apr 20

First fall frost

Oct 13

Growing season

176 days

Onions in nearby zones

Onions in Zone 5b (colder) Onions in Zone 6b (warmer) Full Onions grow guide Zone 6a planting calendar

Other crops in Zone 6a

Tomatoes in Zone 6a Peppers in Zone 6a Cucumbers in Zone 6a Lettuce in Zone 6a Zucchini in Zone 6a Carrots in Zone 6a Beans (bush) in Zone 6a Peas in Zone 6a Broccoli in Zone 6a Spinach in Zone 6a Kale in Zone 6a Garlic in Zone 6a Potatoes in Zone 6a Squash (winter) in Zone 6a Corn in Zone 6a Radishes in Zone 6a Beets in Zone 6a Eggplant in Zone 6a Basil in Zone 6a Cilantro in Zone 6a Parsley in Zone 6a Pumpkins in Zone 6a Sunflowers in Zone 6a

Frequently asked questions

When should I start onions in Zone 6a?

Start onions seeds indoors around Feb 9 (Zone 6a).

Can I direct sow onions in Zone 6a?

Onions is best started indoors and transplanted in Zone 6a rather than direct sown.

Can I plant onions in the fall in Zone 6a?