Cold hardiness & minimum temperature

Is Peace lily (Spathiphyllum wallisii)cold hardy? Hardiness zone & min temp

Also called spathiphyllum, closet plant, white sails.

About Peace lily

Spathiphyllum wallisii · also called spathiphyllum, closet plant · flowering

Peace lily is a shade-loving tropical aroid that wilts theatrically the moment it is thirsty and bounces back within an hour of a soak. Its white "flowers" are modified leaves called spathes. Tolerant of low light, fussy about tap water, mildly toxic to pets.

Spathiphyllum is native to the humid understorey of tropical American rainforests (notably central and southern Mexico, with related species through tropical America and Malesia), growing in shaded, consistently moist forest floors near streams.

A tender evergreen perennial grown indoors in cool climates. RHS confirms it is poisonous like other arums and the sap irritates skin; ASPCA classifies it as toxic to cats and dogs via insoluble calcium oxalate, causing oral pain, drooling and stomach upset.

Cold limit: USDA 11-12 (indoor-only) · RHS H1b (18-24°C)

Sources: rhs.org.uk, aspca.org, en.wikipedia.org

What peace lily's hardiness rating actually means

Peace lily 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 11-12 (indoor-only) — 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). Peace lily has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Peace lily hardiness — frequently asked questions

Is peace lily cold hardy?

Peace lily 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. Peace lily can only live outside year-round in genuinely frost-free climates (roughly USDA 11-12 (indoor-only)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature peace lily can survive?

Minimum survivable temperature is roughly about 10 °C (sustained cold below this is damaging). Peace lily has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is peace lily?

Peace lily is rated USDA 11-12 (indoor-only) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can peace lily 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 peace lily 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.