Plant care
Pleiospilos simulanstemperature & humidity
Pleiospilos simulans
More about pleiospilos simulans
Ideal temperature for pleiospilos simulans
Aim for 10-27°C (50-80°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 10°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Pleiospilos simulans is frost-tender (USDA 9-11 (indoor in most US homes), RHS H2). 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 pleiospilos simulans
Pleiospilos simulans sits happiest at around 30-50% relative humidity. Prefers dry, arid air and dislikes humidity and stagnant, still conditions. Never mist. Good ventilation keeps the broad fleshy leaves dry and helps prevent the fungal rot that over-plump mesembs are prone to. 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.
Pleiospilos simulans temperature & humidity — frequently asked questions
What temperature is best for pleiospilos simulans?
Pleiospilos simulans grows best between 10-27°C (50-80°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 pleiospilos simulans tolerate?
Pleiospilos simulans starts to suffer below roughly 10°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 pleiospilos simulans need?
Pleiospilos simulans prefers about 30-50% relative humidity. Prefers dry, arid air and dislikes humidity and stagnant, still conditions. Never mist. Good ventilation keeps the broad fleshy leaves dry and helps prevent the fungal rot that over-plump mesembs are prone to.
How do I raise humidity for pleiospilos simulans?
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 pleiospilos simulans live outside?
Pleiospilos simulans is rated for USDA zone 9-11 (indoor in most US homes) and RHS hardiness H2. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More pleiospilos simulans care
In the UK? Keeping pleiospilos simulans warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full pleiospilos simulans care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.