Cold hardiness & minimum temperature

Is Calamondin orange (Citrus × microcarpa)cold hardy? Hardiness zone & min temp

Also called calamansi, calamondin, Philippine lime, Panama orange, Citrofortunella microcarpa, Citrus mitis.

More about calamondin orange

About Calamondin orange

Citrus × microcarpa · also called calamansi, calamondin · edible

Calamondin is a compact, evergreen citrus prized as a fruiting houseplant and patio tub tree. It carries fragrant white blossoms and small, sour orange fruit almost year-round. Give it the sunniest spot, evenly moist free-draining soil, and frost protection. ASPCA lists it as toxic to cats, dogs, and horses, so site it out of pets' reach.

Cold limit: USDA 8b-10 outdoors (hardy to about -7°C/20°F when mature); potted and overwintered indoors elsewhere (15-29°C)

Watch for — Sudden leaf drop: Citrus resents abrupt changes in light, temperature, or watering; allow 3-4 weeks to acclimatise after moving it indoors or outdoors.

What calamondin orange's hardiness rating actually means

Calamondin orange 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 8b-10 outdoors (hardy to about -7°C/20°F when mature); potted and overwintered indoors elsewhere — 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 5 °C (and never frost). Calamondin orange has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for calamondin orange as it gets too cold:

Below about about 5 °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 calamondin orange go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °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 calamondin orange can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Calamondin orange hardiness — frequently asked questions

Is calamondin orange cold hardy?

Calamondin orange 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. Calamondin orange can only live outside year-round in genuinely frost-free climates (roughly USDA 8b-10 outdoors (hardy to about -7°C/20°F when mature); potted and overwintered indoors elsewhere); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature calamondin orange can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Calamondin orange has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is calamondin orange?

Calamondin orange is rated USDA 8b-10 outdoors (hardy to about -7°C/20°F when mature); potted and overwintered indoors elsewhere and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can calamondin orange survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °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 calamondin orange below its minimum temperature?

Below about about 5 °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.