When should I plant Purple Kohlrabi in Zone 4b?

Start Purple Kohlrabi seeds indoors around Mar 20. Transplant outdoors after Apr 10. Expect first harvest around May 20.

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 Purple Kohlrabi in Zone 4b?

Yes. Purple Kohlrabi needs 55 days to harvest. Zone 4b has a 157-day growing season, which is sufficient. You can plant up to 4 successions.

Growing Purple Kohlrabi in Zone 4b

Zone 4b has cold winters and a moderate growing season. Timing is key for Purple Kohlrabi 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 3 weeks (up to 4x)

Zone4b

Last FrostMay 1

First FrostOct 5

Season Length157 days

Days to Harvest55

SunFull Sun

Frost ToleranceModerate

Spacing4/sqft (6" apart)

When to Plant Purple Kohlrabi in Zone 4b

Start Seeds Indoors: Mar 20

Start Purple Kohlrabi seeds indoors around Mar 20 (6 weeks before last frost). Optimal germination temperature: 65°F. Germinates in 5–10 days.

Transplant Outdoors: Apr 10

Transplant Purple Kohlrabi seedlings outdoors after Apr 10. 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 20

First harvest approximately May 20 (~40 days from transplant). Continue harvesting until first frost (Oct 5).

Fall Planting: Aug 10

For a fall harvest, plant Purple Kohlrabi around Aug 10 (8 weeks before first frost).

Purple Kohlrabi 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

Plan Your Purple Kohlrabi Garden

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

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