Plant care
Guernsey Lilytemperature & humidity
Nerine sarniensis
More about guernsey lily
Ideal temperature for guernsey lily
Temperature kills fewer guernsey lily 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 5–28°C (requires frost-free minimum of 5°C) (41–82°F) is fine; the spot you put the plant in matters more. Below roughly 5°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Guernsey Lily is frost-tender (USDA 8–11 (frost-free minimum), 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 guernsey lily
Guernsey Lily sits happiest at around 30–50% relative humidity. Prefers dry conditions, especially during dormancy. In a greenhouse, ventilate freely in summer. Avoid damp, stagnant conditions which encourage botrytis on the flowers. 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.
Guernsey Lily temperature & humidity — frequently asked questions
What temperature is best for guernsey lily?
Guernsey Lily grows best between 5–28°C (requires frost-free minimum of 5°C) (41–82°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 guernsey lily tolerate?
Guernsey Lily starts to suffer below roughly 5°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 guernsey lily need?
Guernsey Lily prefers about 30–50% relative humidity. Prefers dry conditions, especially during dormancy. In a greenhouse, ventilate freely in summer. Avoid damp, stagnant conditions which encourage botrytis on the flowers.
How do I raise humidity for guernsey 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 guernsey lily live outside?
Guernsey Lily is rated for USDA zone 8–11 (frost-free minimum) 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 guernsey lily care
In the UK? Keeping guernsey 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 guernsey lily care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.