Cold hardiness & minimum temperature

Is Elk's Horn Fern (Platycerium alcicorne)cold hardy? Hardiness zone & min temp

Also called Elk's Horn Fern, Alcicorne Staghorn.

More about elk's horn fern

About Elk's Horn Fern

Platycerium alcicorne · also called Elk's Horn Fern, Alcicorne Staghorn · houseplant

Platycerium alcicorne is an epiphytic staghorn fern with rounded, papery shield fronds clasping its mount and slender, forking antler-like fertile fronds. Native to Madagascar and East Africa, it grows on bark and rock rather than in soil. Mounted on a board or in a basket, it wants bright indirect light, good airflow, and a soak-and-dry watering rhythm.

Cold limit: USDA 9-12 outdoors; houseplant in cooler zones · RHS H1b (15-27°C)

What elk's horn fern's hardiness rating actually means

Elk's Horn Fern 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 9-12 outdoors; houseplant in cooler zones — 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). Elk's Horn Fern has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for elk's horn fern 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 elk's horn fern 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 elk's horn fern can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Elk's Horn Fern hardiness — frequently asked questions

Is elk's horn fern cold hardy?

Elk's Horn Fern 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. Elk's Horn Fern can only live outside year-round in genuinely frost-free climates (roughly USDA 9-12 outdoors; houseplant in cooler zones); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature elk's horn fern can survive?

What hardiness zone is elk's horn fern?

Elk's Horn Fern is rated USDA 9-12 outdoors; houseplant in cooler zones and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can elk's horn fern 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 elk's horn fern 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.