Cold hardiness & minimum temperature

Is Breadfruit (Artocarpus altilis)cold hardy? Hardiness zone & min temp

Also called Breadfruit, Ulu.

More about breadfruit

About Breadfruit

Artocarpus altilis · also called Breadfruit, Ulu · tropical

Breadfruit is a fast-growing lowland tropical tree grown for its starchy, carbohydrate-rich fruit. It needs constant warmth, full sun, deep fertile soil and ample moisture, and is strictly frost-tender. Outside true tropics it is a large conservatory specimen. The whole plant exudes a sticky white latex when cut, which can irritate skin.

Cold limit: USDA 10-12 (frost-tender; greenhouse/conservatory in most US and UK) · RHS H1a (21-32°C)

Watch for — Cold and frost damage: Even a brief chill below about 5°C scorches leaves and can kill young trees; protect from any frost and cold draughts.

What breadfruit's hardiness rating actually means

Breadfruit 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 H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. On the US scale that maps to USDA 10-12 (frost-tender; greenhouse/conservatory in most US and UK) — 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 above about 15 °C (warm, never cold). Breadfruit has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for breadfruit as it gets too cold:

Below about above about 15 °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 breadfruit go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above above 15 °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 breadfruit can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

Breadfruit hardiness — frequently asked questions

Is breadfruit cold hardy?

Breadfruit 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. Breadfruit can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (frost-tender; greenhouse/conservatory in most US and UK)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature breadfruit can survive?

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). Breadfruit has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is breadfruit?

Breadfruit is rated USDA 10-12 (frost-tender; greenhouse/conservatory in most US and UK) and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can breadfruit survive winter outside?

It can holiday outdoors in summer once nights are reliably above above 15 °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 breadfruit below its minimum temperature?

Below about above about 15 °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.