Plant care
Blue Star Ferntemperature & humidity
Phlebodium aureum
More about blue star fern
Ideal temperature for blue star fern
Aim for 16-24°C (60-75°F) on the thermostat and you've handled the easy part. The hard part is the half-metre around the plant: window glass that drops to near-freezing on a January night, a radiator pumping out hot dry air, a draught from an opened front door. Move the plant 30 cm and you've usually fixed the problem. Below roughly 16°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Blue Star Fern is frost-tender (USDA 8b-13b (grown outdoors only in frost-free climates; a houseplant elsewhere), RHS H1b (min 10-15°C; can go outside in summer, needs warmth and frost-free protection in winter)). 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 blue star fern
Blue Star Fern sits happiest at around 50-60%+ relative humidity. Native to humid tropical forests, it browns at the frond edges when air drops below about 40%. Aim for 50-60% or higher; a humid bathroom or kitchen, a pebble-and-water tray, or a humidifier all help. Misting gives only brief relief, so grouping plants or a room humidifier is more reliable for steady moisture in the air. 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.
Blue Star Fern temperature & humidity — frequently asked questions
What temperature is best for blue star fern?
Blue Star Fern grows best between 16-24°C (60-75°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 blue star fern tolerate?
Blue Star Fern starts to suffer below roughly 16°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 blue star fern need?
Blue Star Fern prefers about 50-60%+ relative humidity. Native to humid tropical forests, it browns at the frond edges when air drops below about 40%. Aim for 50-60% or higher; a humid bathroom or kitchen, a pebble-and-water tray, or a humidifier all help. Misting gives only brief relief, so grouping plants or a room humidifier is more reliable for steady moisture in the air.
How do I raise humidity for blue star fern?
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 blue star fern live outside?
Blue Star Fern is rated for USDA zone 8b-13b (grown outdoors only in frost-free climates; a houseplant elsewhere) and RHS hardiness H1b (min 10-15°C; can go outside in summer, needs warmth and frost-free protection in winter). Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More blue star fern care
In the UK? Keeping blue star fern warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full blue star fern care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.