Cold hardiness & minimum temperature

Is Mother of Thousands (Kalanchoe daigremontiana)cold hardy? Hardiness zone & min temp

Also called Devil's Backbone, Alligator Plant, Mexican Hat Plant.

More about mother of thousands

About Mother of Thousands

Kalanchoe daigremontiana · also called Devil's Backbone, Alligator Plant · houseplant

Kalanchoe daigremontiana is a succulent native to Madagascar, famous for producing hundreds of tiny plantlets along the leaf margins. These drop and root wherever they land, making it prolific. It requires bright light and minimal watering. The ASPCA lists Kalanchoe as toxic to dogs and cats.

Cold limit: USDA 9-11 · RHS H1c (10-27°C)

Watch for — Leaf yellowing: Often a sign of overwatering or cold draughts. Adjust watering and move away from cold windows.

What mother of thousands's hardiness rating actually means

Mother of Thousands 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 9-11 — 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 5 °C (and never frost). Mother of Thousands has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for mother of thousands 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 mother of thousands 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 mother of thousands can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Mother of Thousands hardiness — frequently asked questions

Is mother of thousands cold hardy?

Mother of Thousands 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. Mother of Thousands can only live outside year-round in genuinely frost-free climates (roughly USDA 9-11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature mother of thousands can survive?

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

What hardiness zone is mother of thousands?

Mother of Thousands is rated USDA 9-11 and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can mother of thousands 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 mother of thousands 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.