Cold hardiness & minimum temperature

Is Episcia 'Moss Agate' (Episcia 'Moss Agate')cold hardy? Hardiness zone & min temp

Also called moss agate episcia, moss agate flame violet.

More about episcia 'moss agate'

About Episcia 'Moss Agate'

Episcia 'Moss Agate' · also called moss agate episcia, moss agate flame violet · flowering

Episcia 'Moss Agate' is a flame-violet cultivar prized for its silvery-green, quilted foliage with darker veining and cheerful red-orange tubular flowers. A creeping gesneriad, it spreads by stolons into a trailing mat ideal for baskets and terrariums. It thrives on warmth, high humidity, bright indirect light and even moisture, and dislikes cold or dry conditions.

Cold limit: USDA 11-12 (frost-tender; grown as a houseplant or under glass in most climates) · RHS H1b (18-27°C)

Watch for — Browning leaf margins: Low humidity or dry, draughty air dries the leaf edges. Keep humidity above 60% with a tray or terrarium and away from radiators and vents.

What episcia 'moss agate''s hardiness rating actually means

Episcia 'Moss Agate' 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 or under glass 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). Episcia 'Moss Agate' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Episcia 'Moss Agate' hardiness — frequently asked questions

Is episcia 'moss agate' cold hardy?

Episcia 'Moss Agate' 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. Episcia 'Moss Agate' can only live outside year-round in genuinely frost-free climates (roughly USDA 11-12 (frost-tender; grown as a houseplant or under glass in most climates)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature episcia 'moss agate' can survive?

What hardiness zone is episcia 'moss agate'?

Episcia 'Moss Agate' is rated USDA 11-12 (frost-tender; grown as a houseplant or under glass in most climates) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can episcia 'moss agate' 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 episcia 'moss agate' 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.