Plant care
Caucasian Lilytemperature & humidity
Lilium monadelphum
More about caucasian lily
Ideal temperature for caucasian lily
Caucasian Lily is comfortable in any room a person is comfortable in, roughly -25°C to 28°C; optimal 12–22°C during growth (-13°F to 82°F; optimal 54–72°F during growth). 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 -25°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Caucasian Lily is comparatively hardy (USDA 4-8, RHS H6). Within that range it tolerates a cold dormant spell outdoors; outside it, grow it in a container you can move under cover or overwinter in a cool but frost-free spot. Hardiness assumes an established plant in well-drained soil — a wet, cold root zone kills far more plants than cold air alone.
Humidity for caucasian lily
Caucasian Lily sits happiest at around Moderate to high — 50–70% relative humidity. As a mountain meadow and forest-edge plant, it is accustomed to relatively cool, moderately humid conditions. Tolerates the typical humidity of UK temperate gardens well. As always with lilies, good air circulation through the planting reduces the risk of Botrytis in wet summers. 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.
Caucasian Lily temperature & humidity — frequently asked questions
What temperature is best for caucasian lily?
Caucasian Lily grows best between -25°C to 28°C; optimal 12–22°C during growth (-13°F to 82°F; optimal 54–72°F during growth). 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 caucasian lily tolerate?
Caucasian Lily starts to suffer below roughly -25°C. It tolerates a cold dormant period within USDA 4-8, but a wet cold root zone is more dangerous than cold air.
What humidity does caucasian lily need?
Caucasian Lily prefers about Moderate to high — 50–70% relative humidity. As a mountain meadow and forest-edge plant, it is accustomed to relatively cool, moderately humid conditions. Tolerates the typical humidity of UK temperate gardens well. As always with lilies, good air circulation through the planting reduces the risk of Botrytis in wet summers.
How do I raise humidity for caucasian lily?
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 caucasian lily live outside?
Caucasian Lily is rated for USDA zone 4-8 and RHS hardiness H6. Within that range it can stay outdoors; outside it, grow it in a moveable container and protect the roots from a wet, cold winter.
More caucasian lily care
In the UK? Keeping caucasian lily warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full caucasian lily care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.