Growing Brussels Sprouts in Zone 3a

Zone 3a has harsh winters and a short growing season. Start Brussels Sprouts early indoors to maximize your harvest window. Last frost: May 22. First frost: Sep 12.

Planting Calendar

Indoor

Outdoor

Harvest

Apr 10Sep 12

Season: May 22 – Sep 12 (113 days)

Zone3a

Last FrostMay 22

First FrostSep 12

Season Length113 days

Days to Harvest100

SunFull Sun

Frost ToleranceModerate

Spacing24/sqft

When to Plant Brussels Sprouts in Zone 3a

Start Seeds Indoors: Apr 10

Start Brussels Sprouts seeds indoors around Apr 10 (6 weeks before last frost). Optimal germination temperature: 70°F. Germinates in 5–10 days.

Transplant Outdoors: May 8

Transplant Brussels Sprouts seedlings outdoors after May 8. Wait until soil temperature reaches 50°F. Space plants at 24/sqft. Harden off plants for a week before moving outside.

Harvest: Aug 6

First harvest approximately Aug 6 (~90 days from transplant). Continue harvesting until first frost (Sep 12).

Fall Planting: May 23

For a fall harvest, plant Brussels Sprouts around May 23 (16 weeks before first frost).

Companion Planting

✅ Thyme✅ Nasturtiums✅ Onions✅ Garlic

❌ Beans❌ Strawberries

Brussels Sprouts 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 Brussels Sprouts in Zone 3a?

Start Brussels Sprouts seeds indoors around Apr 10. Transplant outdoors after May 8. Expect first harvest around Aug 6.

What is the last frost date for Zone 3a?

The average last spring frost date for Zone 3a is May 22. The first fall frost averages Sep 12, giving a 113-day growing season.

Can I grow Brussels Sprouts in Zone 3a?

Yes. Brussels Sprouts needs 100 days to harvest. Zone 3a has a 113-day growing season, which is sufficient.

What is the best month to plant Brussels Sprouts in Zone 3a?

The best time to start Brussels Sprouts in Zone 3a is Apr. Begin seeds indoors around Apr 10, then transplant outdoors after the last frost date of May 22.

What companion plants grow well with Brussels Sprouts?

Good companion plants for Brussels Sprouts include Thyme, Nasturtiums, Onions, Garlic. Avoid planting Brussels Sprouts near Beans, Strawberries.

How long does Brussels Sprouts take to harvest?

Brussels Sprouts takes approximately 100 days from planting to harvest. In Zone 3a, expect your first harvest around Aug 6.

Plan Your Brussels Sprouts Garden

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

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