Cold hardiness & minimum temperature

Is Aluminum Plant (Watermelon Pilea) (Pilea cadierei)cold hardy? Hardiness zone & min temp

Also called Aluminum Plant, Watermelon Pilea, Watermelon Plant, Aluminium Plant.

More about aluminum plant (watermelon pilea)

About Aluminum Plant (Watermelon Pilea)

Pilea cadierei · also called Aluminum Plant, Watermelon Pilea · houseplant

The Aluminum Plant (Pilea cadierei) is a compact foliage houseplant in the nettle family, prized for oval green leaves splashed with metallic silver. It thrives in bright indirect light, warmth, high humidity and evenly moist soil, and stays bushy with regular pinching. The ASPCA lists it as non-toxic to dogs, cats and horses.

Cold limit: USDA 11-12 (frost-tender; grown as a houseplant elsewhere; RHS hardiness H1c) (16-24°C)

Watch for — Brown, crispy leaf tips and edges: A sign of low humidity or dry air. Raise humidity with a pebble tray, grouping, or a terrarium; keep away from heating vents and cold drafts.

What aluminum plant (watermelon pilea)'s hardiness rating actually means

Aluminum Plant (Watermelon Pilea) 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 (frost-tender; grown as a houseplant elsewhere; RHS hardiness H1c) — 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). Aluminum Plant (Watermelon Pilea) has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for aluminum plant (watermelon pilea) 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 aluminum plant (watermelon pilea) 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 aluminum plant (watermelon pilea) can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Aluminum Plant (Watermelon Pilea) hardiness — frequently asked questions

Is aluminum plant (watermelon pilea) cold hardy?

Aluminum Plant (Watermelon Pilea) 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. Aluminum Plant (Watermelon Pilea) can only live outside year-round in genuinely frost-free climates (roughly USDA 11-12 (frost-tender; grown as a houseplant elsewhere; RHS hardiness H1c)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature aluminum plant (watermelon pilea) can survive?

What hardiness zone is aluminum plant (watermelon pilea)?

Aluminum Plant (Watermelon Pilea) is rated USDA 11-12 (frost-tender; grown as a houseplant elsewhere; RHS hardiness H1c) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can aluminum plant (watermelon pilea) 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 aluminum plant (watermelon pilea) 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.