Cold hardiness & minimum temperature

Is Common African Violet (Saintpaulia ionantha)cold hardy? Hardiness zone & min temp

Also called African Violet, Usambara Violet, Cape Marigold (trade misnomer, avoid).

More about common african violet

About Common African Violet

Saintpaulia ionantha · also called African Violet, Usambara Violet · houseplant

Common African Violet is the world's most popular flowering houseplant, producing velvety rosettes of dark green leaves and clusters of cheerful violet, purple, pink, or white flowers almost year-round indoors. It thrives under controlled warmth, indirect light, and consistent moisture. ASPCA non-toxic — completely safe for pets.

Cold limit: USDA 11-12 (indoor-only in most homes) · RHS H1c (18-27°C)

Watch for — White ring marks on leaves: Permanent damage caused by cold water or cold draughts touching the leaves. Always use room-temperature water and avoid cold window draughts, especially in winter.

What common african violet's hardiness rating actually means

Common African Violet 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 11-12 (indoor-only in most homes) — 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). Common African Violet has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Common African Violet hardiness — frequently asked questions

Is common african violet cold hardy?

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

What is the minimum temperature common african violet can survive?

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

What hardiness zone is common african violet?

Common African Violet is rated USDA 11-12 (indoor-only in most homes) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can common african violet 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 common african violet 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.