Growing kohlrabi in zone 4a
(Zone 4a = an average winter low of -30°F to -25°F.)
In USDA zone 4a, the typical last spring frost is May 12 and the first fall frost is September 28. Here is when to plant kohlrabi against those dates.
Typical timing
Zone 4a planting schedule
Evidence trail
How these dates are built
Sprout applies the cited planting offsets to the typical zone 4a frost anchors. The result is a planning baseline for the zone, not a local weather forecast.
- USDA Plant Hardiness Zone Map, 2023USDA Agricultural Research Service / Oregon State University PRISM Group. Supports the USDA hardiness-zone band.
- U.S. Climate Normals 1991-2020NOAA National Centers for Environmental Information. Supports the median spring and fall freeze dates.
- Growing Kohlrabi in the Home GardenIowa State University Extension and Outreach. Supports direct-sowing timing (normalized), fall direct-sowing timing (normalized), and days to maturity (direct).
Method note
Direct-sow early spring (cool-season, withstands light frost; central-Iowa early-to-mid-April mapped to about 2 to 4 weeks before last frost), fall direct-sow mid-July to mid-August (mapped to about 8 to 12 weeks before first fall frost), 50-60 days to harvest, 6-8 inch in-row spacing in 18-24 inch rows, 1/4-1/2 inch depth, 6+ hours sun, 1 inch water per week, and pH 6-7 from this page.
These are zone 4a averages
Computed from 795 ZIP codes in zone 4a. Your town's frost dates vary; enter your ZIP for dates built on your nearest weather station.
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Put these dates to work
The plant profile covers spacing, light, water, soil, and source-backed timing details.