Plant care
Blood-red Bertoloniatemperature & humidity
Bertolonia sanguinea
More about blood-red bertolonia
Ideal temperature for blood-red bertolonia
Aim for 19–28°C (66–82°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 19°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Blood-red Bertolonia is frost-tender (USDA 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 blood-red bertolonia
Blood-red Bertolonia sits happiest at around 75–95% relative humidity. Extremely high humidity is essential. This is a strict terrarium species in temperate climates — ambient room humidity almost never meets its needs. Closed terrariums with gentle airflow provide the ideal microclimate. 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.
Blood-red Bertolonia temperature & humidity — frequently asked questions
What temperature is best for blood-red bertolonia?
Blood-red Bertolonia grows best between 19–28°C (66–82°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 blood-red bertolonia tolerate?
Blood-red Bertolonia starts to suffer below roughly 19°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 blood-red bertolonia need?
Blood-red Bertolonia prefers about 75–95% relative humidity. Extremely high humidity is essential. This is a strict terrarium species in temperate climates — ambient room humidity almost never meets its needs. Closed terrariums with gentle airflow provide the ideal microclimate.
How do I raise humidity for blood-red bertolonia?
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 blood-red bertolonia live outside?
Blood-red Bertolonia is rated for USDA zone 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 blood-red bertolonia care
In the UK? Keeping blood-red bertolonia warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full blood-red bertolonia care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.