Growing Brussels Sprouts in Zone 4a

Zone 4a has cold winters and a moderate growing season. Timing is key for Brussels Sprouts in this zone. Last frost: May 5. First frost: Oct 1.

Planting Calendar

Indoor

Outdoor

Harvest

Mar 24Oct 1

Season: May 5 – Oct 1 (149 days)

Zone4a

Last FrostMay 5

First FrostOct 1

Season Length149 days

Days to Harvest100

SunFull Sun

Frost ToleranceModerate

Spacing24/sqft

When to Plant Brussels Sprouts in Zone 4a

Start Seeds Indoors: Mar 24

Start Brussels Sprouts seeds indoors around Mar 24 (6 weeks before last frost). Optimal germination temperature: 70°F. Germinates in 5–10 days.

Transplant Outdoors: Apr 21

Transplant Brussels Sprouts seedlings outdoors after Apr 21. Wait until soil temperature reaches 50°F. Space plants at 24/sqft. Harden off plants for a week before moving outside.

Harvest: Jul 20

First harvest approximately Jul 20 (~90 days from transplant). Continue harvesting until first frost (Oct 1).

Fall Planting: Jun 11

For a fall harvest, plant Brussels Sprouts around Jun 11 (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 4a?

Start Brussels Sprouts seeds indoors around Mar 24. Transplant outdoors after Apr 21. Expect first harvest around Jul 20.

What is the last frost date for Zone 4a?

The average last spring frost date for Zone 4a is May 5. The first fall frost averages Oct 1, giving a 149-day growing season.

Can I grow Brussels Sprouts in Zone 4a?

Yes. Brussels Sprouts needs 100 days to harvest. Zone 4a has a 149-day growing season, which is sufficient.

What is the best month to plant Brussels Sprouts in Zone 4a?

The best time to start Brussels Sprouts in Zone 4a is Mar. Begin seeds indoors around Mar 24, then transplant outdoors after the last frost date of May 5.

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 4a, expect your first harvest around Jul 20.

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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