Cold hardiness & minimum temperature

Is red nerve plant (Fittonia albivenis 'Red Star')cold hardy? Hardiness zone & min temp

Also called red nerve plant, Red Star nerve plant, mosaic plant.

More about red nerve plant

About red nerve plant

Fittonia albivenis 'Red Star' · also called red nerve plant, Red Star nerve plant · houseplant

A compact, low-growing tropical houseplant prized for its striking deep-green leaves etched with vivid crimson-red veins. Rarely exceeds 20 cm tall, making it ideal for terrariums, desk displays, and dish gardens. Demands consistently moist soil and high humidity — it will famously droop and recover when thirsty. Confirmed non-toxic to pets and children by the ASPCA.

Cold limit: USDA 11–12 · RHS H1a (16–26°C)

Watch for — Brown leaf tips and edges: Almost always caused by low humidity, cold draughts, or direct sun. Move to a more sheltered, humid position; consider a terrarium or pebble humidity tray. Trim brown edges with clean scissors and improve conditions to prevent recurrence.

What red nerve plant's hardiness rating actually means

red nerve plant 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 H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. On the US scale that maps to USDA 11–12 — 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 above about 15 °C (warm, never cold). red nerve plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for red nerve plant as it gets too cold:

Below about above about 15 °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 red nerve plant go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above above 15 °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 red nerve plant can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

red nerve plant hardiness — frequently asked questions

Is red nerve plant cold hardy?

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

What is the minimum temperature red nerve plant can survive?

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). red nerve plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is red nerve plant?

red nerve plant is rated USDA 11–12 and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can red nerve plant survive winter outside?

It can holiday outdoors in summer once nights are reliably above above 15 °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 red nerve plant below its minimum temperature?

Below about above about 15 °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.