Kohlrabi is a perennial grown for the harvest, ready about 55 days after sowing. It's hardy across USDA zones 2 through 11. Its flowers are a moderate draw for honeybees and native bees, even though the harvest is the prize. As a brassica (the cabbage family), give it a fresh bed each year — away from where its relatives just grew — so the soil-borne pests and diseases of the family never get a foothold.
Zones
2-11
pH Range
5.5-8.5
Sun
Part Sun
Days to Maturity
55
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What Kohlrabi is
Kohlrabi grows as a perennial and reaches around a foot at maturity.
How to grow Kohlrabi
Kohlrabi grows in USDA zones 2 through 11 and is ready to harvest about 55 days after planting. Kohlrabi does best in part sun — at least 4 hours of direct sun a day — and soil from pH 5.5 to 8.5, on well-drained ground. It needs around 1,100 growing degree days to mature and a growing season of at least 60 frost-free days, which is why climate matters as much as soil.
USDA Zones
2-11
USDA PHZM 2023
Soil pH
5.5 - 8.5
USDA PLANTS Database
Sun
Part Sun
plant_species_v5.csv
Drainage
well (dry spells)
plant_species_v5.csv
Frost Tolerance
41°F
plant_species_v5.csv
Days to Maturity
55 days
Kohlrabi.
UMass-Veg; Cornell
GDD Required
1100+
plant_species_v5.csv
Mature Height
1 ft
plant_species_v5.csv
Frost-Free Days
60+
plant_species_v5.csv
Start the season right
Plant kohlrabi in part sun with at least 4 hours of direct sun, once the soil has warmed and frost risk has passed.
Match the soil
Kohlrabi prefers pH 5.5 to 8.5 (USDA PLANTS Database). A quick soil test from your local Extension lab tells you whether to add lime or sulfur to land in band.
Water steadily
Keep the root zone evenly moist through establishment. A 2–3 inch mulch layer holds moisture without waterlogging.
Harvest at maturity
Kohlrabi is ready about 55 days after sowing (UMass-Veg; Cornell). Watch for cultivar-specific ripeness cues and pick at peak.
Good to know
Good news for pet owners — kohlrabi isn't known to be toxic to dogs or cats. (Source: ASPCA.)
Kohlrabi offers moderate value to bees and other pollinators. (Source: Xerces Society, Pollinator Partnership.)
Where Kohlrabi thrives
On hardiness alone, kohlrabi grows across most of the country — its range (USDA zones 2 through 11) is unusually wide. Zone is only the starting point, though: the soil pH, drainage, and frost dates on your specific land decide how well it actually does.
Zones 2–11·Where Kohlrabi growsOpen map →
Continental US shown — Alaska and US Pacific territories sit outside the federal map's polygon dataset.
On USDA hardiness-zone overlap, Kohlrabi can grow in these states:
See if Kohlrabi will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether kohlrabi actually takes — we score it against the real conditions at your address.
Three things about your exact spot that zone averages miss:
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Frequently Asked Questions
Can I grow Kohlrabi in my zone?
Kohlrabi grows in USDA hardiness zones 2 through 11 (USDA PHZM 2023). Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.
How long does Kohlrabi take to grow?
Kohlrabi is ready to harvest about 55 days after planting (UMass-Veg; Cornell). Your local frost dates and soil temperature move that window earlier or later.
When should you plant Kohlrabi?
Most growers plant kohlrabi after the last spring frost, once the soil has warmed, leaving enough of the season for its 60-day frost-free need. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
How much sun does Kohlrabi need?
Kohlrabi does well in partial sun — around 4 hours of direct sun, and it takes some afternoon shade in stride. That flexibility makes it a good match for a bed the house or a nearby tree shades for part of the day. A Growable Ground report maps how the sun actually falls on your land, hour by hour, so you can set it where the light lines up.
What soil does Kohlrabi need?
Kohlrabi prefers soil pH 5.5 to 8.5, on well-drained ground (USDA PLANTS Database). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Does Kohlrabi attract pollinators?
Yes — kohlrabi's flowers are a solid nectar source for honeybees and native bees (Xerces Society, Pollinator Partnership).
Is Kohlrabi safe for pets?
Kohlrabi is not known to be toxic to dogs or cats based on available data (ASPCA). Always supervise pets around new plantings.