Cold hardiness & minimum temperature

Is Spotted Sinningia (Sinningia guttata)cold hardy? Hardiness zone & min temp

Also called Spotted Sinningia, Spotted Gloxinia.

More about spotted sinningia

About Spotted Sinningia

Sinningia guttata · also called Spotted Sinningia, Spotted Gloxinia · flowering

Sinningia guttata is a tuberous gesneriad native to the Atlantic Forest of Brazil, producing upright stems to about 40 cm topped with white, maroon-spotted tubular flowers. It grows from a caudex tuber and enters dormancy after flowering, at which point watering should be reduced significantly until new growth resumes. Provide bright, indirect light and avoid splashing water on leaves to prevent spotting. The ASPCA lists the Sinningia genus (Gloxinia) as non-toxic to cats and dogs; individual species not separately verified should be treated as mildly toxic until confirmed.

Cold limit: USDA 10–12 (indoor in most climates) · RHS H1b (16–26 °C (active growth); above 10 °C dormancy minimum)

Watch for — Failure to re-emerge from dormancy: Tubers stored too wet or too cold over winter may rot; store the dormant tuber barely moist at 10–15 °C and check periodically for shrivelling.

What spotted sinningia's hardiness rating actually means

Spotted Sinningia 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 10–12 (indoor in most climates) — 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). Spotted Sinningia has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Spotted Sinningia hardiness — frequently asked questions

Is spotted sinningia cold hardy?

Spotted Sinningia 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. Spotted Sinningia can only live outside year-round in genuinely frost-free climates (roughly USDA 10–12 (indoor in most climates)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature spotted sinningia can survive?

What hardiness zone is spotted sinningia?

Spotted Sinningia is rated USDA 10–12 (indoor in most climates) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can spotted sinningia 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 spotted sinningia 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.