When should I plant Onion in Zone 6b?

Start Onion seeds indoors around Feb 4. Transplant outdoors after Mar 18. Expect first harvest around Jun 6.

What is the last frost date for Zone 6b?

The average last spring frost date for Zone 6b is Apr 15. The first fall frost averages Oct 22, giving a 190-day growing season.

Can I grow Onion in Zone 6b?

Yes. Onion needs 110 days to harvest. Zone 6b has a 190-day growing season, which is sufficient.

🧅

🧅 Growing Onion in Zone 6b

Zone 6b has mild winters and a long growing season — good conditions for Onion. Last frost: Apr 15. First frost: Oct 22.

Planting Calendar

Indoor

Outdoor

Harvest

Feb 4Oct 22

Season: Apr 15 – Oct 22 (190 days)

Zone6b

Last FrostApr 15

First FrostOct 22

Season Length190 days

Days to Harvest110

SunFull Sun

Frost ToleranceModerate

Spacing9/sqft (4" apart)

When to Plant Onion in Zone 6b

Start Seeds Indoors: Feb 4

Start Onion seeds indoors around Feb 4 (10 weeks before last frost). Optimal germination temperature: 70°F. Germinates in 7–14 days.

Transplant Outdoors: Mar 18

Transplant Onion seedlings outdoors after Mar 18. Wait until soil temperature reaches 45°F. Space plants at 9/sqft (4" apart). Harden off plants for a week before moving outside.

Harvest: Jun 6

First harvest approximately Jun 6 (~80 days from transplant). Continue harvesting until first frost (Oct 22).

Companion Planting

✅ Strawberries✅ Cabbage✅ Beets✅ Lettuce✅ Carrots✅ Tomatoes

❌ Beans❌ Peas

Onion in Other Zones

1a 1b 2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a 11b 12a 12b 13a 13b

Plan Your Onion Garden

Track Onion from seed to harvest with personalized frost dates, watering recommendations, and companion planting visualization.

Start Free Onion Growing Guide