How to Grow Kohlrabis USA

By the SoilCommander Editorial Team, under the guidance of Nitin Sharma, Co-Founder · · How we check our facts

On this page
  1. Kohlrabi (Brassica oleracea Gongylodes Group)
  2. Quick Facts
  3. At a Glance
  4. Diseases
  5. Pests
  6. Soil & Growing Conditions
  7. Growth Stages
  8. Harvest & Storage
  9. Kohlrabi, a Fast Above-Ground Cabbage-Family Globe
  10. Plan your Kohlrabis planting
  11. Growing Kohlrabi in another region
  12. Sources
  13. Frequently Asked Questions

In the US, sow kohlrabi in early spring as soon as the ground can be worked, making small plantings every two to three weeks for a steady harvest. Pick the stems while still young — around 1 inch (2.5cm) in diameter and no larger than 2–3 inches (5–7.5cm) — since bigger, older kohlrabi turns tough, woody, and loses flavor.

The short answer

Ready in
42–84 days
Site
soil pH 6–6.5
Biggest risk
Brassica downy mildew

Core growing advice on this page is checked against named horticultural sources — see References.

Kohlrabi (Brassica oleracea Gongylodes Group)

Young kohlrabi seedlings growing in a tray — “Kohlrabi EPT-Jungpflanzen-2--Josef Schlaghecken” by Schlaghecken Josef is licensed under CC BY-SA 4.0.

12 sources cited · Verified

Quick Facts

A purple kohlrabi globe growing in the ground — “Brassica oleracea var. gongylodes 01” by Σ64 is licensed under CC BY 4.0.
“Brassica oleracea var. gongylodes 01” by Σ64 is licensed under CC BY 4.0.
Factor Value
Soil pH 6 - 6.5
Optimal growing temp 54-64°F (12-18°C)
Minimum survivable temp 28°F (-2°C)
Time to harvest 42-84 days
Drainage Chalk, Loam, Clay, Sand; fertile, moisture-retentive soil, less nitrogen-demanding than other brassicas
Lifecycle biennial, grown as annual
Edible parts swollen stem, young leaves
Documented problems 3 diseases, 5 pests

At a Glance

A purple kohlrabi globe growing in the ground — “Brassica oleracea var. gongylodes 01” by Σ64 is licensed under CC BY 4.0.
“Brassica oleracea var. gongylodes 01” by Σ64 is licensed under CC BY 4.0.
Brassica oleracea Gongy… Kohlrabi Brassica downy mildew White blister Club root Flea beetles Cabbage root fly (US: c… Cabbage caterpillars Slugs Mealy cabbage aphid DISEASES PESTS

Diseases

Young kohlrabi seedlings growing in a tray — “Kohlrabi EPT-Jungpflanzen-2--Josef Schlaghecken” by Schlaghecken Josef is licensed under CC BY-SA 4.0.
“Kohlrabi EPT-Jungpflanzen-2--Josef Schlaghecken” by Schlaghecken Josef is licensed under CC BY-SA 4.0.
Brassica downy mildew

Hyaloperonospora brassicae (syn. Peronospora parasitica)

White blister

Albugo candida

Plasmodiophora brassicae

Pests

Young kohlrabi seedlings growing in a tray — “Kohlrabi EPT-Jungpflanzen-2--Josef Schlaghecken” by Schlaghecken Josef is licensed under CC BY-SA 4.0.
“Kohlrabi EPT-Jungpflanzen-2--Josef Schlaghecken” by Schlaghecken Josef is licensed under CC BY-SA 4.0.
Flea beetles

Chrysomelidae: Alticini (various spp.)

Cabbage root fly (US: cabbage maggot)

Delia radicum

Cabbage caterpillars

Pieris brassicae; Pieris rapae; Pieris napi; Mamestra brassicae; Plutella xylostella

Slugs

Gastropoda (slugs, various spp.)

Mealy cabbage aphid

Brevicoryne brassicae

Soil & Growing Conditions

Young kohlrabi seedlings growing in a tray — “Kohlrabi EPT-Jungpflanzen-2--Josef Schlaghecken” by Schlaghecken Josef is licensed under CC BY-SA 4.0.
“Kohlrabi EPT-Jungpflanzen-2--Josef Schlaghecken” by Schlaghecken Josef is licensed under CC BY-SA 4.0.

Soil pH range

6 6.5

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Growth Stages

A bolted kohlrabi plant in flower — “Brassica oleracea gongylodes without sun” by Crusier is licensed under CC BY-SA 3.0.
“Brassica oleracea gongylodes without sun” by Crusier is licensed under CC BY-SA 3.0.
Stage BBCH Notes
Sowing and germination 0 Sow 1.5cm deep, indoors in spring for transplanting 3-4 weeks later, or outdoors March-July (August in mild areas) once soil exceeds 50°F (10°C); germinates in under 2 weeks (RHS).
Thinning and establishment 1 Thin to a final spacing of 15cm apart in rows 30cm apart once seedlings reach 2.5cm tall or show their first true leaves; water regularly until well rooted (RHS).
Stem swelling 4 Keep soil consistently moist -- drought causes woodiness and bolting; hand-weed near plants to avoid damaging the swelling stem; protect with insect-proof mesh and against slugs/snails (RHS).
Harvest 8 Harvest once the swollen stem is between golf-ball and tennis-ball size for best tenderness; larger specimens turn woody. Harvest window runs May-November, or into December in milder areas (RHS).

Harvest & Storage

A pair of harvested green kohlrabi — “A pair of cabbage turnips in home” by Peachyeung316 is licensed under CC BY-SA 4.0.
“A pair of cabbage turnips in home” by Peachyeung316 is licensed under CC BY-SA 4.0.

When to pick: Harvest when young, between golf-ball and tennis-ball size (5-6cm diameter); larger specimens lose flavour and turn woody, especially in hot dry weather

Plan your Kohlrabis planting

When to sow and plant Kohlrabis depends on your own frost dates. Check the USA vegetable planting calendar, or the month-by-month guides that cover Kohlrabis: October, November. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Kohlrabi in another region

Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.

Sources

  3. Sow in early spring in small plantings every 2-3 weeks for a continuous supply; plants can be started indoors or under glass for transplanting as soon as the ground is workable, and midsummer sowings are possible alongside late cabbage. Sow 1/4 to 1/2in deep, thinning seedlings to 2-5in apart and transplanting the surplus to fill gaps. Needs fertile soil, adequate moisture and weed control to sustain the rapid growth that gives good quality. HARVEST from about 1in stem diameter and continue to 2-3in: large, older kohlrabi is tough, woody and can be off-flavoured, and stems over 3in develop woody fibres, especially lower down. Pests: imported cabbageworm, cabbage looper, diamondback moth and cabbage maggot; diseases managed by clean seed, good practice and rotation.

These 3 sources are specific to this region. The full list of 12 sources behind this guide (Clemson Cooperative Extension, FAO EcoCrop, Royal Horticultural Society and others) is in the references of our UK guide to kohlrabi; they describe the plant itself, which is the same wherever it grows.

Frequently Asked Questions

How long does kohlrabi take to grow?

Typically 42–84 days, depending on cultivar and growing conditions.

What soil pH does kohlrabi need?

A pH of about 6–6.5. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.

What problems affect kohlrabi?

Our data links 3 diseases and 5 pests to this crop. See the sections above for each one and how to manage it.

Plan next season before the problems start

Almost everything on this page resolves to your own frost dates rather than the calendar — the last spring frost moves by roughly two months between zone 3 and zone 10. The USA Garden Planner works from your zone so the timing is already decided before the season starts.

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Instant PDF download · Written for US growing conditions

SoilCommander Editorial Team — under the guidance of Nitin Sharma, Co-Founder

Every growing guide is checked against RHS, USDA Cooperative Extension, and other named horticultural authorities before publishing. How we check our facts.

How this guide is put together

The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against USDA hardiness-zone and frost-date data, with Cooperative Extension sources cited directly where one exists for a crop. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.

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Last verified 2026-09-02

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