Plant care
Tamanutemperature & humidity
Calophyllum inophyllum
More about tamanu
Ideal temperature for tamanu
Temperature kills fewer tamanu 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 20–35°C (68–95°F) is fine; the spot you put the plant in matters more. Below roughly 20°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Tamanu is frost-tender (USDA 10b–12, RHS H1a). 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 tamanu
Tamanu sits happiest at around 60–90% RH relative humidity. Native to tropical coastal environments with high humidity. Tolerates lower humidity when established but performs best in humid, maritime conditions. Not suited to arid climates. 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.
Tamanu temperature & humidity — frequently asked questions
What temperature is best for tamanu?
Tamanu grows best between 20–35°C (68–95°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 tamanu tolerate?
Tamanu starts to suffer below roughly 20°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 tamanu need?
Tamanu prefers about 60–90% RH relative humidity. Native to tropical coastal environments with high humidity. Tolerates lower humidity when established but performs best in humid, maritime conditions. Not suited to arid climates.
How do I raise humidity for tamanu?
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 tamanu live outside?
Tamanu is rated for USDA zone 10b–12 and RHS hardiness H1a. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More tamanu care
In the UK? Keeping tamanu warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full tamanu care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.