Kohlrabi is a quick, cool-season cabbage relative with two seasons. In spring, direct seed or transplant it 1 to 2 weeks before your last frost (Utah State); UMN sows from mid-April to early May in Minnesota. For fall, sow in mid to late summer: UMN sows again in July. In Texas, plant from mid-August to November depending on region (Texas A&M), and in Florida from September or October through March (UF/IFAS).
Kohlrabi is grown for its swollen, crisp stem, which tastes like a mild, sweet broccoli stalk. Spring varieties are ready in 35 to 45 days in UMN's guide, and Utah State lists 'Quickstar' at 40 days, 'Grand Duke' at 50 and 'White' or 'Purple Vienna' at 60. That speed makes kohlrabi a good crop to fit between longer-season plantings.
Spring dates by last frost
The table counts back from your average last spring frost. Transplants or seed go out 1 to 2 weeks before the frost (Utah State). If you start transplants, UMN sows them indoors 4 to 6 weeks before transplanting, at 60 to 70°F. The last column adds 40 to 60 days for harvest.
| Average last spring frost | Start seeds indoors | Transplant or direct seed | Harvest (about 40 to 60 days) |
|---|---|---|---|
| Mar 1 | Jan 4 – Jan 18 | Feb 15 – Feb 22 | Mar 27 – Apr 23 |
| Mar 15 | Jan 18 – Feb 1 | Mar 1 – Mar 8 | Apr 10 – May 7 |
| Apr 1 | Feb 4 – Feb 18 | Mar 18 – Mar 25 | Apr 27 – May 24 |
| Apr 15 | Feb 18 – Mar 4 | Apr 1 – Apr 8 | May 11 – Jun 7 |
| May 1 | Mar 6 – Mar 20 | Apr 17 – Apr 24 | May 27 – Jun 23 |
| May 15 | Mar 20 – Apr 3 | May 1 – May 8 | Jun 10 – Jul 7 |
| Jun 1 | Apr 6 – Apr 20 | May 18 – May 25 | Jun 27 – Jul 24 |
Illinois sows small amounts every 2 to 3 weeks through early spring for a longer harvest. Don't keep sowing into warm weather: UMN says to avoid spring plantings after about May 1 in Minnesota, because kohlrabi is best at 65 to 75°F and Utah State says it does best at or below 75°F.
Fall kohlrabi
Fall is often the better season, because the bulbs size up as the weather cools. Count back from your average first fall frost. Larger, slower "giant" types take about 2 months (UMN), so sow them 8 to 10 weeks before the frost. Quick varieties can go in later: Utah State plants early varieties 50 days before the date you want to harvest, and that date can be 2 to 3 weeks after the first frost, since the plants take light frosts.
| Average first fall frost | Sow giant or storage types | Last sowing for quick (40 to 50 day) varieties |
|---|---|---|
| Sep 15 | Jul 7 – Jul 21 | Aug 11 |
| Oct 1 | Jul 23 – Aug 6 | Aug 27 |
| Oct 15 | Aug 6 – Aug 20 | Sep 10 |
| Nov 1 | Aug 23 – Sep 6 | Sep 27 |
| Nov 15 | Sep 6 – Sep 20 | Oct 11 |
UMN sows fall kohlrabi in July and says late-July plantings are ready before a hard freeze. Illinois makes one or two midsummer plantings alongside late cabbage. Summer-sown seedlings need steady water, and Illinois shades them in hot weather.
Texas and Florida dates
In warm-winter areas kohlrabi is a fall-through-spring crop. Texas A&M's fall vegetable guide gives average fall planting dates by region:
| Texas region | Fall planting date |
|---|---|
| Region I (Panhandle) | Aug 15 |
| Region II | Sep 1 |
| Region III | Sep 10 |
| Region IV | Oct 1 |
| Region V (far south) | Nov 1 |
In Florida, UF/IFAS's month-by-month calendar lists kohlrabi from September through March in North Florida, October through March in Central Florida, and October through February in South Florida. UF/IFAS says kohlrabi is timed like cabbage, recommends 'White Vienna' (55 days), 'Kolibri' and 'Terek', and puts harvest at about 40 days from transplants.
Planting and spacing
| Step | What extension sources say |
|---|---|
| Seed depth | ¼ to ½ inch (UMN, Illinois) |
| Spacing | Thin to 4 inches (UMN, UF/IFAS), 2 to 5 inches (Illinois) or 6 inches in rows 1 foot apart (Utah State); give giant fall types about 12 inches (UMN) |
| Transplants | 5 to 6 weeks to grow (Utah State); 4 to 6 weeks indoors at 60 to 70°F (UMN) |
| Water | About 1 inch a week (UMN), 1 to 2 inches (Utah State); dry spells make the bulbs tough |
| Rotation | Keep the whole cabbage family out of the same spot for 4 years (UMN) |
Harvest
Pick kohlrabi young. Illinois starts harvesting once the bulb is about 1 inch across and keeps going until it reaches 2 to 3 inches; above about 3 inches it gets woody. UMN also harvests at 2 to 3 inches. Giant fall varieties are the exception and stay tender at a larger size. Cut the stem below the bulb, trim the leaves, and refrigerate: about 2 weeks (UMN, Illinois), or 2 to 3 weeks at 32°F (Utah State). The young leaves can be cooked like other greens.
Where kohlrabi goes in the garden
Kohlrabi is a cabbage-family crop, so it shares neighbors, pests and rotation with broccoli and cabbage. See what to plant with cabbage for companions, and when to plant broccoli and cabbage for the rest of the family's dates. Because it is small and fast, kohlrabi also fits along the edge of a bed or between slower plants.
Frequently asked questions
When should I plant kohlrabi?
In spring, direct seed or transplant 1 to 2 weeks before your last frost (Utah State); UMN sows from mid-April to early May in Minnesota. For a fall crop, sow in mid to late summer, about 5 to 10 weeks before the first fall frost.
Can you plant kohlrabi in the fall?
Yes, and the bulbs often taste better in cool weather. UMN sows again in July, and Utah State plants quick varieties 50 days before the harvest date, which can be 2 to 3 weeks after the first frost.
When do you plant kohlrabi in Texas?
Texas A&M lists average fall planting dates of Aug 15 in Region I, Sep 1 in Region II, Sep 10 in Region III, Oct 1 in Region IV and Nov 1 in Region V.
When do you plant kohlrabi in Florida?
UF/IFAS lists kohlrabi from September through March in North Florida, October through March in Central Florida, and October through February in South Florida.
How long does kohlrabi take to grow?
About 35 to 60 days, depending on the variety: UMN gives 35 to 45 days for spring types, and Utah State lists Quickstar at 40, Grand Duke at 50 and White or Purple Vienna at 60. Giant fall types take about 2 months.
Why is my kohlrabi bolting instead of forming a bulb?
Cold is the usual cause. Utah State says average temperatures below 45°F during growth can trigger flowering, and UMN warns that a late frost or more than a week of nights below 50°F can do the same.
How big should kohlrabi be when you pick it?
About 2 to 3 inches across. Illinois says bulbs larger than about 3 inches get woody, except for giant varieties bred to grow large.
Enter your frost dates to see cabbage-family planting weeks and every other spring and fall crop.
Open itSources
- Virginia Cooperative Extension, "Companion Planting in Gardening" (SPES-620P)
- University of Maryland Extension, "Vegetable Succession and Companion Planting"
- Oregon State University Extension, "Companion Planting"
- Penn State Extension, "Herbs Make Good Plant Partners and Companions"
- University of Minnesota Extension, "Planting the vegetable garden"
- USDA Plant Hardiness Zone Map
- NOAA NCEI U.S. Climate Normals (frost/freeze data)
- University of Minnesota Extension, "Growing kohlrabi"
- University of Illinois Extension, "Kohlrabi" (home vegetable gardening)
- Utah State University Extension, "Kohlrabi in the Garden"
- UF/IFAS Gardening Solutions, "Kohlrabi"
- Texas A&M AgriLife Extension, "Fall Vegetable Gardening Guide for Texas"
- University of Florida IFAS Gardening Solutions, "What to Plant by Month" (text version)
Pairings are summarized in our own words from extension-service guidance. Research support for many companion effects is limited, so treat them as good habits, not guarantees.