Plant care
Macarthur Palmtemperature & humidity
Ptychosperma macarthurii
More about macarthur palm
Ideal temperature for macarthur palm
Temperature kills fewer macarthur palm plants than you'd think. What kills them is the micro-climate within a normal-temperature room — a leaf pressed against single-glazed winter glass, the hot dry updraft directly above a radiator, the cold blast from an AC vent. The thermostat reading at 10 to 35°C (50 to 95°F) is fine; the spot you put the plant in matters more. Below roughly 10°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Macarthur Palm is frost-tender (USDA 10b–11, RHS H1b). It cannot survive a frost, so in most of the US and UK it lives indoors year-round or summers outside and comes back in well before the first autumn frost — once nights drop toward 10-12°C is the cue, not the first frost warning. Acclimate it over a week when moving between indoors and out so the leaves do not shock.
Humidity for macarthur palm
Macarthur Palm sits happiest at around 60–80% relative humidity. Prefers high humidity characteristic of its rainforest habitat. Indoors, place on a pebble tray with water or group with other plants to raise local humidity. Will tolerate moderate humidity but benefits from regular misting in centrally heated interiors. The usual low-humidity tell is crisp brown leaf tips and edges while the soil moisture is fine — a sign the air, not the watering, is the problem. If you need to raise it, the reliable methods are grouping plants together, standing the pot on a tray of damp pebbles (the pot above the waterline, never in it), or running a small humidifier in winter when indoor heating dries the air most. Misting is the least effective — it raises humidity for minutes, not hours.
Macarthur Palm temperature & humidity — frequently asked questions
What temperature is best for macarthur palm?
Macarthur Palm grows best between 10 to 35°C (50 to 95°F). Keep it out of cold draughts, off freezing windowsills in winter, and away from the hot dry air directly above radiators — the extremes matter far more than the average room temperature.
How cold can macarthur palm tolerate?
Macarthur Palm starts to suffer below roughly 10°C. It is frost-tender and will be damaged or killed by a frost, so bring it indoors once nights fall toward 10-12°C.
What humidity does macarthur palm need?
Macarthur Palm prefers about 60–80% relative humidity. Prefers high humidity characteristic of its rainforest habitat. Indoors, place on a pebble tray with water or group with other plants to raise local humidity. Will tolerate moderate humidity but benefits from regular misting in centrally heated interiors.
How do I raise humidity for macarthur palm?
Group it with other plants, stand the pot on a tray of damp pebbles (kept above the waterline), or run a small humidifier in winter. Misting only helps for a few minutes, so it is the weakest option for a plant that genuinely needs more humidity.
Can macarthur palm live outside?
Macarthur Palm is rated for USDA zone 10b–11 and RHS hardiness H1b. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More macarthur palm care
In the UK? Keeping macarthur palm warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full macarthur palm care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.