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When to plant Kohlrabi

Computed from land-grant Extension planting-window rules (cited below), localized to real ZIP-level median frost dates, not a single national guess. These are national-generic rules by hardiness class; individual state Extension offices layer their own regional adjustment on top (earlier in the Deep South, later in the Upper Midwest). Enter your ZIP for your own dates, or read the four representative locations below.

Planting windows and crop timing here are computed from USDA/NOAA climate data and the university extension sources cited below, not a site visit or soil test. Treat this as a starting point: local conditions vary, and a local nursery or extension office can advise on your exact site. See our full Disclaimer.

Representative timing, by climate band

When to plant Kohlrabi in four US climates

Each column is the most nursery-dense location in our directory within that USDA zone band, computed from that location's own real median frost dates, not a made-up example.

Stage Zones 1-5 (cold winters)
Fort Plain, NY 		Zones 6-7 (temperate)
McMinnville, TN 		Zones 8-9 (warm)
Apopka, FL 		Zones 10-13 (hot, frost rare or absent)
Loxahatchee, FL
Start seed indoors Not available Not available Not available –
Direct-sow outside Mar 25–Apr 22 Feb 24–Mar 24 Jan 13–Feb 10 –
Transplant outside Not available Not available Not available –
Fall planting Aug 11–Sep 8 Sep 4–Oct 2 Nov 3–Dec 1 –
Expected harvest May 14–Jun 26 Apr 15–May 28 Mar 4–Apr 16 –

Zones 10-13 (hot, frost rare or absent) (Loxahatchee, FL): Frost is rare here (about 359 frost-free days a year); most years see little or no hard freeze. This is a hardy crop. In climates like this one, hardy and semi-hardy crops typically go in during the cooler months (fall through late winter), not on a frost-relative schedule.

Kohlrabi goes into the ground two to six weeks before your last frost. Colorado State University Extension's hardy rule (Fact Sheet 7.212) calls for two to four weeks before frost; Purdue Extension (HO-186-W) puts the same hardy tier four to six weeks before, the same systematic gap this page finds between the two sources on several hardy crops. Both windows are published here rather than merged into one.

Soil should read 40°F at seeding, from Colorado State; Purdue's soil-temperature table has no kohlrabi row to compare it against. Days to maturity run 50 to 65, combining Colorado State's 50 with Missouri Extension's 55 to 65. NC State's 22-to-32-day figure is excluded here; it reads as anomalously short for kohlrabi, likely describing an immature harvest, and no other source corroborates it.

Kohlrabi also takes a fall planting, four to eight weeks before your first fall frost, per Purdue's explicit list. Because kohlrabi is hardy, a cold-winter climate can seed it two to six weeks ahead of frost without concern; a mild-winter climate shifts the same window earlier and gets a longer fall season on top of it.

Kohlrabi is a direct-seed crop at most nurseries, sold as seed for both the spring and fall windows above rather than as started transplants.

Frost hardiness

Hardy. Tolerates hard frost. Can go in the ground before the last frost date.

Minimum soil temperature

40°F

For direct sowing/germination, where an Extension source stated it.

Days to maturity

50–65

Sourcing notes

From direct seed. CSU's hardy window (2-4wk before) and PURDUE's (4-6wk before) unioned and flagged, consistent with the systematic gap seen across hardy crops in this dataset. CSU soil temp 40F (no PURDUE Table 3 row for kohlrabi). DTM: CSU 50, MOEXT 55-65 - combined range; NCSU's 22-32-day figure looks anomalously short (likely an immature-harvest convention) and was excluded, flagged. Fall figure per PURDUE's explicit list.

Related crops

Growing zones for this crop

Nurseries near these locations

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Sources