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🧅 Growing Onion in Zone 1a

Zone 1a has harsh winters and a short growing season. Start Onion early indoors to maximize your harvest window. Last frost: May 25. First frost: Aug 28.

Season Too Short

Onion needs 110 days to harvest, but Zone 1a has only a 95-day growing season. Consider short-season varieties or season extension techniques (cold frames, row covers).

Zone1a

Last FrostMay 25

First FrostAug 28

Season Length95 days

Days to Harvest110

SunFull Sun

Frost ToleranceModerate

Spacing9/sqft (4" apart)

When to Plant Onion in Zone 1a

Start Seeds Indoors: Mar 16

Start Onion seeds indoors around Mar 16 (10 weeks before last frost). Optimal germination temperature: 70°F. Germinates in 7–14 days.

Transplant Outdoors: Apr 27

Transplant Onion seedlings outdoors after Apr 27. Wait until soil temperature reaches 45°F. Space plants at 9/sqft (4" apart). Harden off plants for a week before moving outside.

Harvest: Jul 16

First harvest approximately Jul 16 (~80 days from transplant). Continue harvesting until first frost (Aug 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 1a?

Start Onion seeds indoors around Mar 16. Transplant outdoors after Apr 27. Expect first harvest around Jul 16.

What is the last frost date for Zone 1a?

The average last spring frost date for Zone 1a is May 25. The first fall frost averages Aug 28, giving a 95-day growing season.

Can I grow Onion in Zone 1a?

Zone 1a has a 95-day growing season, which may be too short for Onion (110 days needed). Consider short-season varieties or season extension techniques.

What is the best month to plant Onion in Zone 1a?

The best time to start Onion in Zone 1a is Mar. Begin seeds indoors around Mar 16, then transplant outdoors after the last frost date of May 25.

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 1a, expect your first harvest around Jul 16.

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