Cold hardiness & minimum temperature

Is Moses in the Cradle (Tradescantia spathacea)cold hardy? Hardiness zone & min temp

Also called Moses in the cradle, boat lily, oyster plant, Rhoeo spathacea.

More about moses in the cradle

About Moses in the Cradle

Tradescantia spathacea · also called Moses in the cradle, boat lily · houseplant

Moses in the cradle is a tough, rosette-forming tropical with sword-shaped leaves that are glossy green above and rich purple beneath. Tiny white flowers nestle in boat-shaped bracts at the leaf bases, giving the plant its name. It is undemanding, drought-tolerant once established, and excellent for bright windowsills or as a colourful groundcover in warm climates.

Cold limit: USDA 9-11 (houseplant in cooler regions) · RHS H1b (18-27°C)

What moses in the cradle's hardiness rating actually means

Moses in the Cradle 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 9-11 (houseplant in cooler regions) — 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). Moses in the Cradle has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for moses in the cradle 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 moses in the cradle 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 moses in the cradle can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Moses in the Cradle hardiness — frequently asked questions

Is moses in the cradle cold hardy?

Moses in the Cradle 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. Moses in the Cradle can only live outside year-round in genuinely frost-free climates (roughly USDA 9-11 (houseplant in cooler regions)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature moses in the cradle can survive?

What hardiness zone is moses in the cradle?

Moses in the Cradle is rated USDA 9-11 (houseplant in cooler regions) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can moses in the cradle 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 moses in the cradle 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.