How to Grow Siberian Kale USA

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

On this page
  1. Siberian Kale (Brassica napus var. pabularia)
  2. At a Glance
  3. Quick Facts
  4. Soil & Growing Conditions
  5. Growth Stages
  6. Harvest & Storage
  7. Diseases
  8. Pests
  9. Plan your Siberian Kale planting
  10. Growing Siberian Kale in another region
  11. Sources
  12. Frequently Asked Questions

Siberian kale (Brassica napus var. pabularia) — annual or biennial grown as an annual.

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

Siberian Kale (Brassica napus var. pabularia)

Siberian Kale ('Ragged Jack') growing in a heritage seed bed — “CBG Fruit Veg Island - Anniversary Heirloom Beds, Brassica napus 'Ragged Jack' Siberian Kale 150627 (20329896065)” by cultivar413 from Fallbrook, California is licensed under CC BY 2.0.

3 sources cited · Verified

At a Glance

A young Siberian Kale plant showing purple leaf veining
A young Siberian Kale plant showing purple leaf veining. Photo by Stephen Barstow, CC BY 4.0, via GBIF.
Brassica napus var. pab… Siberian Kale Brassica downy mildew Club root Aphids Cabbage caterpillars Flea beetles DISEASES PESTS

Quick Facts

Siberian Kale ('Ragged Jack') growing in a heritage seed bed
Siberian Kale ('Ragged Jack') growing in a heritage seed bed. Photo: “CBG Fruit Veg Island - Anniversary Heirloom Beds, Brassica napus 'Ragged Jack' Siberian Kale 150627 (20329896065)” by cultivar413 from Fallbrook, California, CC BY 2.0.
Factor Value
Soil texture fertile soil (RHS)
Drainage well-drained
Lifecycle annual or biennial grown as an annual
Edible parts leaves

Soil & Growing Conditions

A young Siberian Kale plant showing purple leaf veining
A young Siberian Kale plant showing purple leaf veining. Photo by Stephen Barstow, CC BY 4.0, via GBIF.

Water: keep well-watered (RHS); benefits from compost or nitrogen-rich fertiliser worked in before planting (Properly Rooted)

Growth Stages

Close-up of Siberian Kale's distinctive purple stem base
Close-up of Siberian Kale's distinctive purple stem base. Photo by Stephen Barstow, CC BY 4.0, via GBIF.
Stage BBCH Notes
Sowing 0 Sow indoors mid-spring, prick out to modules or individual pots (RHS); or direct sow after last frost up to six weeks before first frost (Properly Rooted).
Transplanting 1 Transplant out early summer, May-July, in rows 60cm apart (RHS).
Low, clustered leaf growth 3 Grows low and clustered, closer to the ground, rather than from a central stalk like most kale; keep well-watered and net against birds and insects (Properly Rooted, RHS).
Cut-and-come-again harvest 8 Harvest leaves at any size with a sharp knife; exceptionally cold-hardy, down to 10°F, mature plants to -20°F (Properly Rooted).

Harvest & Storage

A mature Siberian Kale plant showing its purple stem
A mature Siberian Kale plant showing its purple stem. Photo by Stephen Barstow, CC BY 4.0, via GBIF.

When to pick: Harvest leaves at any size, from baby to full-grown, cutting with a sharp knife (Properly Rooted). Exceptionally cold-hardy: hardy down to 10°F, mature plants may withstand as low as -20°F (Properly Rooted).

Diseases

Siberian Kale ('Ragged Jack') growing in a heritage seed bed
Siberian Kale ('Ragged Jack') growing in a heritage seed bed. Photo: “CBG Fruit Veg Island - Anniversary Heirloom Beds, Brassica napus 'Ragged Jack' Siberian Kale 150627 (20329896065)” by cultivar413 from Fallbrook, California, CC BY 2.0.
Brassica downy mildew
moderate

Hyaloperonospora brassicae (syn. Peronospora parasitica)

RHS names this directly for the Pabularia Group.

moderate

Plasmodiophora brassicae

RHS names this directly for the Pabularia Group: club root.

Pests

Siberian Kale with purple stems growing through snow
Siberian Kale with purple stems growing through snow. Photo by Stephen Barstow, CC BY 4.0, via GBIF.
low

Aphididae (various spp.)

Properly Rooted names this directly: aphids.

Cabbage caterpillars
moderate

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

RHS names this directly for the Pabularia Group: cabbage caterpillars.

Flea beetles
moderate

Chrysomelidae: Alticini (various spp.)

RHS names this directly for the Pabularia Group: flea beetle.

Plan your Siberian Kale planting

When to sow and plant Siberian Kale depends on your own frost dates. Check the USA vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Siberian Kale in another region

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

Sources

The full list of 3 sources behind this guide (Properly Rooted, Royal Horticultural Society, Seed Ambassadors Project) is in the references of our UK guide to siberian kale; they describe the plant itself, which is the same wherever it grows.

Frequently Asked Questions

What problems affect siberian kale?

Our data links 2 diseases and 3 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.

Get the USA Garden Planner →

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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.

Vegetable Growing Guides USA

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Last verified 2026-08-29

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