Plant care
Amaryllistemperature & humidity
Hippeastrum hybrids
More about amaryllis
Ideal temperature for amaryllis
Aim for 15-24C (active growth); 10-13C for dormancy (60-75F (active growth); 50-55F for dormancy) 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 15°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Amaryllis is frost-tender (USDA USDA zones 9-11 outdoors; grown as an indoor pot/forced bulb in cooler climates., RHS undefined). 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 amaryllis
Amaryllis sits happiest at around Average household humidity (around 40-50%) relative humidity. Amaryllis is not fussy about humidity and grows well in normal indoor air. No misting or humidifier is needed; good airflow actually helps prevent fungal issues like red blotch on stalks and leaves. 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.
Amaryllis temperature & humidity — frequently asked questions
What temperature is best for amaryllis?
Amaryllis grows best between 15-24C (active growth); 10-13C for dormancy (60-75F (active growth); 50-55F for dormancy). 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 amaryllis tolerate?
Amaryllis starts to suffer below roughly 15°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 amaryllis need?
Amaryllis prefers about Average household humidity (around 40-50%) relative humidity. Amaryllis is not fussy about humidity and grows well in normal indoor air. No misting or humidifier is needed; good airflow actually helps prevent fungal issues like red blotch on stalks and leaves.
How do I raise humidity for amaryllis?
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 amaryllis live outside?
Amaryllis is rated for USDA zone USDA zones 9-11 outdoors; grown as an indoor pot/forced bulb in cooler climates.. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More amaryllis care
In the UK? Keeping amaryllis warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full amaryllis care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.