Cold hardiness & minimum temperature

Is Fine-lined Living Stone (Lithops gracilidelineata)cold hardy? Hardiness zone & min temp

Also called Fine-veined Living Stone, Delicate-lined Mimicry Plant.

More about fine-lined living stone

About Fine-lined Living Stone

Lithops gracilidelineata · also called Fine-veined Living Stone, Delicate-lined Mimicry Plant · houseplant

Lithops gracilidelineata is a South African stone-plant distinguished by intricate fine lines and channels on its flat, translucent lobe surface, which act as light windows to internal chlorophyll. It produces white or pale yellow flowers in autumn. Non-toxic to pets. Strict seasonal watering and maximum sunlight are the two non-negotiable care requirements.

Cold limit: USDA 10-11 (indoor-only in most climates) · RHS H1c (10-30°C)

Watch for — Rot from seasonal watering mistakes: Watering in summer or during the winter leaf-split phase is the primary cause of plant loss. Strictly follow the seasonal schedule.

What fine-lined living stone's hardiness rating actually means

Fine-lined Living Stone is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Its RHS rating of H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10-11 (indoor-only in most climates) — 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 5 °C (and never frost). Fine-lined Living Stone has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for fine-lined living stone as it gets too cold:

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches.
A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover.
Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.

Can fine-lined living stone go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually.
Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C.
It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

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 fine-lined living stone can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Fine-lined Living Stone hardiness — frequently asked questions

Is fine-lined living stone cold hardy?

Fine-lined Living Stone is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Indoor-only in almost every home. Fine-lined Living Stone can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (indoor-only in most climates)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature fine-lined living stone can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Fine-lined Living Stone has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is fine-lined living stone?

Fine-lined Living Stone is rated USDA 10-11 (indoor-only in most climates) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can fine-lined living stone survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually. Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C. It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

What happens to fine-lined living stone below its minimum temperature?

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches. A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover. Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.