Plant care
Mexican Achimenestemperature & humidity
Achimenes mexicana
More about mexican achimenes
Ideal temperature for mexican achimenes
Aim for 20–28°C active growth (day); 17–19°C (night minimum); 13–15°C winter storage (68–82°F active growth (day); 62–65°F (night minimum); 55–59°F winter storage) 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 20°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Mexican Achimenes is frost-tender (USDA 10–12, RHS H1b). 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 mexican achimenes
Mexican Achimenes sits happiest at around 50–70% relative humidity. Warm, humid conditions replicate its tropical Mexican habitat. Buds fail to open if night temperatures drop below 17°C (62°F) or humidity is chronically low; brown buds that do not open are the tell-tale symptom. 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.
Mexican Achimenes temperature & humidity — frequently asked questions
What temperature is best for mexican achimenes?
Mexican Achimenes grows best between 20–28°C active growth (day); 17–19°C (night minimum); 13–15°C winter storage (68–82°F active growth (day); 62–65°F (night minimum); 55–59°F winter storage). 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 mexican achimenes tolerate?
Mexican Achimenes 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 mexican achimenes need?
Mexican Achimenes prefers about 50–70% relative humidity. Warm, humid conditions replicate its tropical Mexican habitat. Buds fail to open if night temperatures drop below 17°C (62°F) or humidity is chronically low; brown buds that do not open are the tell-tale symptom.
How do I raise humidity for mexican achimenes?
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 mexican achimenes live outside?
Mexican Achimenes is rated for USDA zone 10–12 and RHS hardiness H1b. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More mexican achimenes care
In the UK? Keeping mexican achimenes warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full mexican achimenes care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.