Growing Bok Choy in Zone 4b

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

Planting Calendar

Indoor

Outdoor

Harvest

Mar 20Oct 5

Season: May 1 – Oct 5 (157 days) · Succession: plant every 2 weeks (up to 8x)

Zone4b

Last FrostMay 1

First FrostOct 5

Season Length157 days

Days to Harvest45

SunPart Sun / Part Shade

Frost ToleranceModerate

Spacing4/sqft (6" apart)

When to Plant Bok Choy in Zone 4b

Start Seeds Indoors: Mar 20

Start Bok Choy seeds indoors around Mar 20 (6 weeks before last frost). Optimal germination temperature: 65°F. Germinates in 4–8 days.

Transplant Outdoors: Apr 24

Transplant Bok Choy seedlings outdoors after Apr 24. Wait until soil temperature reaches 45°F. Space plants at 4/sqft (6" apart). Harden off plants for a week before moving outside.

Harvest: May 29

First harvest approximately May 29 (~35 days from transplant). Continue harvesting until first frost (Oct 5).

Fall Planting: Aug 17

For a fall harvest, plant Bok Choy around Aug 17 (7 weeks before first frost).

Companion Planting

✅ Carrots✅ Beets✅ Dill✅ Onions✅ Beans

❌ Strawberries

Bok Choy 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 Bok Choy in Zone 4b?

Start Bok Choy seeds indoors around Mar 20. Transplant outdoors after Apr 24. Expect first harvest around May 29.

What is the last frost date for Zone 4b?

The average last spring frost date for Zone 4b is May 1. The first fall frost averages Oct 5, giving a 157-day growing season.

Can I grow Bok Choy in Zone 4b?

Yes. Bok Choy needs 45 days to harvest. Zone 4b has a 157-day growing season, which is sufficient. You can plant up to 8 successions.

What is the best month to plant Bok Choy in Zone 4b?

The best time to start Bok Choy in Zone 4b is Mar. Begin seeds indoors around Mar 20, then transplant outdoors after the last frost date of May 1.

What companion plants grow well with Bok Choy?

Good companion plants for Bok Choy include Carrots, Beets, Dill, Onions, Beans. Avoid planting Bok Choy near Strawberries.

How long does Bok Choy take to harvest?

Bok Choy takes approximately 45 days from planting to harvest. In Zone 4b, expect your first harvest around May 29.

Plan Your Bok Choy Garden

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

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