Growing Fennel in Zone 3b

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

Planting Calendar

Indoor

Outdoor

Harvest

Apr 17Sep 22

Season: May 15 – Sep 22 (130 days) · Succession: plant every 3 weeks (up to 3x)

Zone3b

Last FrostMay 15

First FrostSep 22

Season Length130 days

Days to Harvest65

SunFull Sun

Frost ToleranceLight

Spacing12/sqft

When to Plant Fennel in Zone 3b

Start Seeds Indoors: Apr 17

Start Fennel seeds indoors around Apr 17 (4 weeks before last frost). Optimal germination temperature: 65°F. Germinates in 7–14 days.

Transplant Outdoors: May 8

Transplant Fennel seedlings outdoors after May 8. Wait until soil temperature reaches 50°F. Space plants at 12/sqft. Harden off plants for a week before moving outside.

Harvest: Jul 2

First harvest approximately Jul 2 (~55 days from transplant). Continue harvesting until first frost (Sep 22).

Fall Planting: Jul 14

For a fall harvest, plant Fennel around Jul 14 (10 weeks before first frost).

Companion Planting

✅ Dill

❌ Tomatoes❌ Peppers❌ Beans❌ Eggplant❌ Kohlrabi

Fennel 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 Fennel in Zone 3b?

Start Fennel seeds indoors around Apr 17. Transplant outdoors after May 8. Expect first harvest around Jul 2.

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 Fennel in Zone 3b?

Yes. Fennel needs 65 days to harvest. Zone 3b has a 130-day growing season, which is sufficient. You can plant up to 3 successions.

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

The best time to start Fennel in Zone 3b is Apr. Begin seeds indoors around Apr 17, then transplant outdoors after the last frost date of May 15.

What companion plants grow well with Fennel?

Good companion plants for Fennel include Dill. Avoid planting Fennel near Tomatoes, Peppers, Beans, Eggplant.

How long does Fennel take to harvest?

Fennel takes approximately 65 days from planting to harvest. In Zone 3b, expect your first harvest around Jul 2.

Plan Your Fennel Garden

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

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