Cold hardiness & minimum temperature

Is Hall's Living Stones (Lithops hallii)cold hardy? Hardiness zone & min temp

Also called Hall's Living Stones, Hall's Pebble Plant.

More about hall's living stones

About Hall's Living Stones

Lithops hallii · also called Hall's Living Stones, Hall's Pebble Plant · houseplant

Lithops hallii is a South African stone mimic with grey to brownish, intricately patterned flat tops and a sturdy, compact body. It is considered a moderately easy Lithops for beginners willing to respect its strict watering calendar. White or yellow daisy-like flowers emerge from the fissure between the leaf pair in autumn.

Cold limit: USDA 10-11 · RHS H1b (5–40°C)

Watch for — Seasonal watering confusion: New growers often water when the plant looks shrivelled, not realising summer and winter shrinkage are part of the dormancy cycle. Follow the calendar, not the plant's appearance during dormancy months.

What hall's living stones's hardiness rating actually means

Hall's Living Stones 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 H1b means: Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season. On the US scale that maps to USDA 10-11 — 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 10 °C (sustained cold below this is damaging). Hall's Living Stones has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for hall's living stones as it gets too cold:

Below about about 10 °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 hall's living stones go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 10 °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 hall's living stones can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Hall's Living Stones hardiness — frequently asked questions

Is hall's living stones cold hardy?

Hall's Living Stones 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. Hall's Living Stones can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature hall's living stones can survive?

What hardiness zone is hall's living stones?

Hall's Living Stones is rated USDA 10-11 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can hall's living stones survive winter outside?

It can holiday outdoors in summer once nights are reliably above 10 °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 hall's living stones below its minimum temperature?

Below about about 10 °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.