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🥦 Growing Cauliflower in Zone 3b

Zone 3b has harsh winters and a short growing season. Start Cauliflower early indoors to maximize your harvest window. Last frost: May 15. First frost: Sep 22.

Planting Calendar

Indoor

Outdoor

Harvest

Apr 3Sep 22

Season: May 15 – Sep 22 (130 days)

Zone3b

Last FrostMay 15

First FrostSep 22

Season Length130 days

Days to Harvest75

SunFull Sun

Frost ToleranceModerate

Spacing1/sqft (12" apart)

When to Plant Cauliflower in Zone 3b

Start Seeds Indoors: Apr 3

Start Cauliflower seeds indoors around Apr 3 (6 weeks before last frost). Optimal germination temperature: 70°F. Germinates in 5–10 days.

Transplant Outdoors: May 1

Transplant Cauliflower seedlings outdoors after May 1. Wait until soil temperature reaches 50°F. Space plants at 1/sqft (12" apart). Harden off plants for a week before moving outside.

Harvest: Jun 30

First harvest approximately Jun 30 (~60 days from transplant). Continue harvesting until first frost (Sep 22).

Fall Planting: Jun 30

For a fall harvest, plant Cauliflower around Jun 30 (12 weeks before first frost).

Companion Planting

✅ Spinach ✅ Celery ✅ Thyme✅ Beans

❌ Tomatoes❌ Strawberries❌ Peas

Cauliflower 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 Cauliflower in Zone 3b?

Start Cauliflower seeds indoors around Apr 3. Transplant outdoors after May 1. Expect first harvest around Jun 30.

What is the last frost date for Zone 3b?

The average last spring frost date for Zone 3b is May 15. The first fall frost averages Sep 22, giving a 130-day growing season.

Can I grow Cauliflower in Zone 3b?

Yes. Cauliflower needs 75 days to harvest. Zone 3b has a 130-day growing season, which is sufficient.

What is the best month to plant Cauliflower in Zone 3b?

The best time to start Cauliflower in Zone 3b is Apr. Begin seeds indoors around Apr 3, then transplant outdoors after the last frost date of May 15.

What companion plants grow well with Cauliflower?

Good companion plants for Cauliflower include Spinach, Celery, Thyme, Beans. Avoid planting Cauliflower near Tomatoes, Strawberries, Peas.

How long does Cauliflower take to harvest?

Cauliflower takes approximately 75 days from planting to harvest. In Zone 3b, expect your first harvest around Jun 30.

Plan Your Cauliflower Garden

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

Start Free Cauliflower Growing Guide