Plant care
Hot Water Planttemperature & humidity
Achimenes longiflora
More about hot water plant
Ideal temperature for hot water plant
Hot Water Plant is comfortable in any room a person is comfortable in, roughly 18-27°C (65-80°F). The mistakes are micro-climates: a north-facing window on a frosty night, a south-facing windowsill in a summer heatwave, the standing draught between an opened kitchen door and the radiator behind it. Read the room around the plant, not the thermostat. Below roughly 18°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Hot Water Plant is frost-tender (USDA 10-12 (grown from rhizomes as tender perennials in most zones), RHS H1c). 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 hot water plant
Hot Water Plant sits happiest at around 50-65% relative humidity. Moderate to high humidity is preferred. In low-humidity environments, leaf tips may brown and flowering can be reduced. Pebble trays or grouping with other tropical plants helps maintain humidity without causing root rot. 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.
Hot Water Plant temperature & humidity — frequently asked questions
What temperature is best for hot water plant?
Hot Water Plant grows best between 18-27°C (65-80°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 hot water plant tolerate?
Hot Water Plant starts to suffer below roughly 18°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 hot water plant need?
Hot Water Plant prefers about 50-65% relative humidity. Moderate to high humidity is preferred. In low-humidity environments, leaf tips may brown and flowering can be reduced. Pebble trays or grouping with other tropical plants helps maintain humidity without causing root rot.
How do I raise humidity for hot water plant?
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 hot water plant live outside?
Hot Water Plant is rated for USDA zone 10-12 (grown from rhizomes as tender perennials in most zones) and RHS hardiness H1c. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More hot water plant care
In the UK? Keeping hot water plant warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full hot water plant care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.