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
Season: May 1 – Oct 5 (157 days) · Succession: plant every 3 weeks (up to 4x)
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 13bFrequently Asked Questions
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.
What is the best month to plant Purple Kohlrabi in Zone 4b?
The best time to start Purple Kohlrabi in Zone 4b is Mar. Begin seeds indoors around Mar 20, then transplant outdoors after the last frost date of May 1.
How long does Purple Kohlrabi take to harvest?
Purple Kohlrabi takes approximately 55 days from planting to harvest. In Zone 4b, expect your first harvest around May 20.
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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