Cold hardiness & minimum temperature

Is Gasteria (Ox Tongue) (Gasteria carinata)cold hardy? Hardiness zone & min temp

Also called Ox Tongue, Ox-tongue, Keeled Ox Tongue, Bredasdorp Gasteria, Cow's Tongue.

More about gasteria (ox tongue)

About Gasteria (Ox Tongue)

Gasteria carinata · also called Ox Tongue, Ox-tongue · houseplant

Gasteria carinata, the keeled ox tongue, is a slow-growing South African succulent with thick, keeled, tongue-shaped leaves that clump into tidy rosettes. It thrives on bright indirect light, infrequent watering and gritty soil, making it forgiving for beginners. Not individually ASPCA-listed, so treat as mildly toxic and verify pet safety with a vet.

Cold limit: USDA 9a-11b (tender; protect from frost, keep above about 5 C / 40 F) (10-25 C)

Watch for — Brown leaf tips and patches: Usually from inconsistent watering, soggy soil or temperature extremes. Keep a steady soak-and-dry rhythm and avoid cold draughts or sudden heat.

What gasteria (ox tongue)'s hardiness rating actually means

Yes — gasteria (ox tongue) is genuinely cold hardy. Rated RHS H6 and USDA 9a-11b (tender; protect from frost, keep above about 5 C / 40 F), 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 9a-11b (tender; protect from frost, keep above about 5 C / 40 F) — 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. Gasteria (Ox Tongue) is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for gasteria (ox tongue) 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 gasteria (ox tongue) go outside or overwinter — and where?

Plant it out within USDA 9a-11b (tender; protect from frost, keep above about 5 C / 40 F) 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 gasteria (ox tongue) can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Gasteria (Ox Tongue) hardiness — frequently asked questions

Is gasteria (ox tongue) cold hardy?

Yes — gasteria (ox tongue) is genuinely cold hardy. Rated RHS H6 and USDA 9a-11b (tender; protect from frost, keep above about 5 C / 40 F), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Gasteria (Ox Tongue) is hardy across USDA 9a-11b (tender; protect from frost, keep above about 5 C / 40 F); 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 gasteria (ox tongue) can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Gasteria (Ox Tongue) is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is gasteria (ox tongue)?

Gasteria (Ox Tongue) is rated USDA 9a-11b (tender; protect from frost, keep above about 5 C / 40 F) and RHS H6 — Hardy throughout the UK and northern Europe.

Can gasteria (ox tongue) survive winter outside?

Plant it out within USDA 9a-11b (tender; protect from frost, keep above about 5 C / 40 F) 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 gasteria (ox tongue) 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.