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🧅 Growing Onion in Zone 8b

Zone 8b has warm winters and an extended growing season — excellent for heat-loving crops like Onion. Last frost: Mar 22. First frost: Nov 10.

Planting Calendar

Indoor

Outdoor

Harvest

Jan 11Nov 10

Season: Mar 22 – Nov 10 (233 days)

Zone8b

Last FrostMar 22

First FrostNov 10

Season Length233 days

Days to Harvest110

SunFull Sun

Frost ToleranceModerate

Spacing9/sqft (4" apart)

When to Plant Onion in Zone 8b

Start Seeds Indoors: Jan 11

Start Onion seeds indoors around Jan 11 (10 weeks before last frost). Optimal germination temperature: 70°F. Germinates in 7–14 days.

Transplant Outdoors: Feb 22

Transplant Onion seedlings outdoors after Feb 22. Wait until soil temperature reaches 45°F. Space plants at 9/sqft (4" apart). Harden off plants for a week before moving outside.

Harvest: May 13

First harvest approximately May 13 (~80 days from transplant). Continue harvesting until first frost (Nov 10).

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

Frequently Asked Questions

When should I plant Onion in Zone 8b?

Start Onion seeds indoors around Jan 11. Transplant outdoors after Feb 22. Expect first harvest around May 13.

What is the last frost date for Zone 8b?

The average last spring frost date for Zone 8b is Mar 22. The first fall frost averages Nov 10, giving a 233-day growing season.

Can I grow Onion in Zone 8b?

Yes. Onion needs 110 days to harvest. Zone 8b has a 233-day growing season, which is sufficient.

What is the best month to plant Onion in Zone 8b?

The best time to start Onion in Zone 8b is Jan. Begin seeds indoors around Jan 11, then transplant outdoors after the last frost date of Mar 22.

What companion plants grow well with Onion?

Good companion plants for Onion include Strawberries, Cabbage, Beets, Lettuce, Carrots, Tomatoes. Avoid planting Onion near Beans, Peas.

How long does Onion take to harvest?

Onion takes approximately 110 days from planting to harvest. In Zone 8b, expect your first harvest around May 13.

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