Plant care
straight-leaved butterworttemperature & humidity
Pinguicula rectifolia
More about straight-leaved butterwort
Ideal temperature for straight-leaved butterwort
Temperature kills fewer straight-leaved butterwort plants than you'd think. What kills them is the micro-climate within a normal-temperature room — a leaf pressed against single-glazed winter glass, the hot dry updraft directly above a radiator, the cold blast from an AC vent. The thermostat reading at 15–27°C (summer active); keep above 0°C in winter (60–80°F; protect from frost) is fine; the spot you put the plant in matters more. Below roughly 15°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
straight-leaved butterwort is frost-tender (USDA 10-11, 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 straight-leaved butterwort
straight-leaved butterwort sits happiest at around 40–80% relative humidity. Tolerates average household humidity (40–50%) during active growth if watering is consistent. During the winter rest the plant benefits from higher ambient humidity around 80%; placing it in a partially open terrarium or on a pebble tray helps. Good air circulation is essential year-round to prevent crown 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.
straight-leaved butterwort temperature & humidity — frequently asked questions
What temperature is best for straight-leaved butterwort?
straight-leaved butterwort grows best between 15–27°C (summer active); keep above 0°C in winter (60–80°F; protect from frost). 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 straight-leaved butterwort tolerate?
straight-leaved butterwort 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 straight-leaved butterwort need?
straight-leaved butterwort prefers about 40–80% relative humidity. Tolerates average household humidity (40–50%) during active growth if watering is consistent. During the winter rest the plant benefits from higher ambient humidity around 80%; placing it in a partially open terrarium or on a pebble tray helps. Good air circulation is essential year-round to prevent crown rot.
How do I raise humidity for straight-leaved butterwort?
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 straight-leaved butterwort live outside?
straight-leaved butterwort is rated for USDA zone 10-11 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 straight-leaved butterwort care
In the UK? Keeping straight-leaved butterwort warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full straight-leaved butterwort care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.