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🧅 Growing Onion in Zone 8a

Zone 8a has warm winters and an extended growing season — excellent for heat-loving crops like Onion. Last frost: Apr 5. First frost: Oct 28.

Planting Calendar

Indoor

Outdoor

Harvest

Jan 25Oct 28

Season: Apr 5 – Oct 28 (206 days)

Zone8a

Last FrostApr 5

First FrostOct 28

Season Length206 days

Days to Harvest110

SunFull Sun

Frost ToleranceModerate

Spacing9/sqft (4" apart)

When to Plant Onion in Zone 8a

Start Seeds Indoors: Jan 25

Start Onion seeds indoors around Jan 25 (10 weeks before last frost). Optimal germination temperature: 70°F. Germinates in 7–14 days.

Transplant Outdoors: Mar 8

Transplant Onion seedlings outdoors after Mar 8. 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 27

First harvest approximately May 27 (~80 days from transplant). Continue harvesting until first frost (Oct 28).

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 8a?

Start Onion seeds indoors around Jan 25. Transplant outdoors after Mar 8. Expect first harvest around May 27.

What is the last frost date for Zone 8a?

The average last spring frost date for Zone 8a is Apr 5. The first fall frost averages Oct 28, giving a 206-day growing season.

Can I grow Onion in Zone 8a?

Yes. Onion needs 110 days to harvest. Zone 8a has a 206-day growing season, which is sufficient.

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

The best time to start Onion in Zone 8a is Jan. Begin seeds indoors around Jan 25, then transplant outdoors after the last frost date of Apr 5.

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 8a, expect your first harvest around May 27.

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