How to Grow Siberian Kale UK

When to Plant Siberian Kale in the UK

When to plant siberian kale in the UK: in Southern England, sow early April to early June. Find your area in the table below.

Region	Sow
Southern England	early April to early June
Midlands	early April to early June
Northern England	early April to early June
Scotland	early April to early June

Southern England - detail & sources

RHS: sow indoors mid-spring, transplant early summer May-July, with no UK-region-specific dates given; this window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.

Midlands - detail & sources

RHS: sow indoors mid-spring, transplant early summer May-July, with no UK-region-specific dates given; this window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.

Northern England - detail & sources

RHS: sow indoors mid-spring, transplant early summer May-July, with no UK-region-specific dates given; this window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.

Scotland - detail & sources

RHS: sow indoors mid-spring, transplant early summer May-July, with no UK-region-specific dates given; this window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.

Quick Facts

Factor	Value
Soil texture	fertile soil (RHS)
Drainage	well-drained
Lifecycle	annual or biennial grown as an annual
Edible parts	leaves

At a Glance

Soil & Growing Conditions

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

Growth Stages

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

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

Brassica downy mildew

moderate

Hyaloperonospora brassicae (syn. Peronospora parasitica)

RHS names this directly for the Pabularia Group.

Club root

moderate

Plasmodiophora brassicae

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

Pests

Aphids

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.

Siberian Kale, Known by its Blue-Green, Purple-Veined Leaves

A distinct, separately-bred cultivar

Seed Ambassadors: Red Russian and Siberian are "the two most well-known varieties" of Russo-Siberian kale, documented and bred separately since the 19th century.

Genuinely cold-hardy

A frost-tolerant kale that keeps growing through snow, in keeping with its Siberian namesake.

Purple veining on blue-green leaves

Siberian kale carries purple leaf veins over a blue-green leaf, a key identifying trait distinguishing it from other kale types.

The distinctive purple stem base

Purple colouration extends down into the stem itself, a trait shared with its close relative Red Russian kale.

A tall, upright habit

A mature plant develops a tall, upright stem with a crown of ragged-edged leaves at the top.

References

1. Properly Rooted - Siberian Kale: A Primer

   A secondary gardening reference rather than a university or horticultural authority, used for growth-habit and hardiness detail specific to Siberian (not Red Russian), not contradicted by the above. Siberian kale produces wide, flat leaves growing closer to the ground, forming a low cluster rather than growing from a central stalk like most other kale. Exceptionally cold-hardy: hardy down to 10°F, mature plants may withstand as low as -20°F; less heat-tolerant than other kale types. Direct sow after last frost up to six weeks before first frost, or start indoors. Benefits from compost or nitrogen-rich fertiliser worked into the soil before planting. Harvest leaves at any size with a sharp knife. Fewer pest/disease problems than other kale types, but still susceptible to aphids, whiteflies, cabbageworm and cabbage looper.

2. Royal Horticultural Society - Brassica napus Pabularia Group | curled kitchen kale

   RHS's general Pabularia Group cultivation page (RHS bundles named cultivars within this group, including Red Russian and other Siberian-type kales, under this Group-level entry and its per-cultivar pages). Grow in fertile, moist but well-drained soil in full sun. Sow indoors mid-spring, prick out to modules/pots, transplant early summer May-July in rows 60cm apart. Keep well-watered, cover with netting against birds/insects. Pests: birds, cabbage caterpillars, cabbage whitefly, cabbage gall weevil, slugs, snails, flea beetle, mealy cabbage aphid, swede midge. Diseases: black rot, club root, brassica downy mildew, foot and root rot, leaf spot, white blister.

3. Seed Ambassadors Project - All About Russian and Siberian Kale (napus kale)

   A specialist seed-heritage source, used for the specific leaf-colour/shape distinction between Siberian and Red Russian that RHS's Group-level page does not draw out (RHS bundles both under one Pabularia Group page); not contradicted by RHS. Red Russian and Siberian are the two most well-known named varieties of Russo-Siberian (Brassica napus) kale in the US, recognised as distinct cultivars, not interchangeable terms. Red Russian: stems and veins red/purple, leaves deep grey/green, flat with toothed edges, documented in Russia since 1885. Siberian (also "Early Siberian"): blue-green, huge, feather-shaped, slightly curled leaves, no red/purple pigmentation, extremely hardy, vigorous, rapid-growing. Both are recognised as genetically distinct parent stock -- modern crosses such as 'Red Ursa' deliberately combine "the broadleaf frills of Siberian with the colour of Red Russian," which would not make sense if they were the same plant.

3 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.