Cold hardiness & minimum temperature

Is Begonia 'Tiny Gem' (Begonia × 'Tiny Gem')cold hardy? Hardiness zone & min temp

Also called tiny gem begonia, miniature rhizomatous begonia.

More about begonia 'tiny gem'

About Begonia 'Tiny Gem'

Begonia × 'Tiny Gem' · also called tiny gem begonia, miniature rhizomatous begonia · houseplant

A dwarf rhizomatous begonia forming a dense low rosette of small, slightly puckered green leaves, often flushed bronze in good light, with delicate pale pink flowers. Its compact size makes it ideal for terrariums, small pots and windowsills. Give it bright indirect light, steady moisture and warmth, and avoid wetting the crown.

Cold limit: USDA 10-11 (indoor in most US and UK homes) · RHS H1b (16-24°C)

What begonia 'tiny gem''s hardiness rating actually means

Begonia 'Tiny Gem' 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 10-11 (indoor in most US and UK 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 10 °C (sustained cold below this is damaging). Begonia 'Tiny Gem' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Begonia 'Tiny Gem' hardiness — frequently asked questions

Is begonia 'tiny gem' cold hardy?

Begonia 'Tiny Gem' 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. Begonia 'Tiny Gem' can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (indoor in most US and UK homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature begonia 'tiny gem' can survive?

What hardiness zone is begonia 'tiny gem'?

Begonia 'Tiny Gem' is rated USDA 10-11 (indoor in most US and UK homes) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can begonia 'tiny gem' 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 begonia 'tiny gem' 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.