Cold hardiness & minimum temperature

Is Tartarian Sea Kale (Crambe tataria)cold hardy? Hardiness zone & min temp

Also called Tartarian sea kale, Tartar bread plant, Steppe kale, Katran.

More about tartarian sea kale

About Tartarian Sea Kale

Crambe tataria · also called Tartarian sea kale, Tartar bread plant · edible

Crambe tataria (also written C. tatarica) is a deeply taprooted herbaceous perennial native to the dry steppes of central and eastern Europe, from Hungary eastward into Ukraine and central Asia. Unlike coastal sea kale (C. maritima), it grows inland on alkaline, well-drained steppe soils and produces fleshy, starch-rich roots that have been used as a radish and bread-flour substitute in Eastern European folk food traditions. It emerges early in spring, produces clouds of white flowers, then dies back completely by mid-summer. No toxicity is recorded; treat as mildly toxic in the absence of an ASPCA confirmed non-toxic listing.

Cold limit: USDA 4-8 · RHS H6 (-30°C to 28°C)

Watch for — Root rot from winter wet: The deep taproot is highly susceptible to rot if soil becomes waterlogged over winter; plant on a raised bed, slope, or in very free-draining soil — this is the primary reason for plant death in cultivation.

What tartarian sea kale's hardiness rating actually means

Yes — tartarian sea kale is genuinely cold hardy. Rated RHS H6 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. On the US scale that maps to USDA 4-8 — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly about −20 to −15 °C. Tartarian Sea Kale is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for tartarian sea kale as it gets too cold:

It tolerates winter lows to about −20 to −15 °C once established.
Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root.
First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.

Can tartarian sea kale go outside or overwinter — and where?

Plant it out within USDA 4-8 and it overwinters with little or no help.
It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy.
The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when tartarian sea kale can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Tartarian Sea Kale hardiness — frequently asked questions

Is tartarian sea kale cold hardy?

Yes — tartarian sea kale is genuinely cold hardy. Rated RHS H6 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Tartarian Sea Kale is hardy across USDA 4-8; it belongs in the ground or a frost-proof container, not on a windowsill, and many types actively need a cold winter to perform.

What is the minimum temperature tartarian sea kale can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Tartarian Sea Kale is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is tartarian sea kale?

Tartarian Sea Kale is rated USDA 4-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can tartarian sea kale survive winter outside?

Plant it out within USDA 4-8 and it overwinters with little or no help. It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy. The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

What happens to tartarian sea kale below its minimum temperature?

It tolerates winter lows to about −20 to −15 °C once established. Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root. First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.