Plant care
Giant Water Lilytemperature & humidity
Nymphaea gigantea
More about giant water lily
Ideal temperature for giant water lily
Aim for 10°C to 35°C (actively grows above 24°C) (50°F to 95°F (actively grows above 75°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
Giant Water Lily 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 giant water lily
Giant Water Lily sits happiest at around Ambient outdoor humidity relative humidity. As an outdoor pond plant in its native range, high ambient tropical humidity is the norm; in temperate climates grow in a heated glasshouse pond where humidity is naturally elevated. 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.
Giant Water Lily temperature & humidity — frequently asked questions
What temperature is best for giant water lily?
Giant Water Lily grows best between 10°C to 35°C (actively grows above 24°C) (50°F to 95°F (actively grows above 75°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 giant water lily tolerate?
Giant Water Lily 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 giant water lily need?
Giant Water Lily prefers about Ambient outdoor humidity relative humidity. As an outdoor pond plant in its native range, high ambient tropical humidity is the norm; in temperate climates grow in a heated glasshouse pond where humidity is naturally elevated.
How do I raise humidity for giant water 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 giant water lily live outside?
Giant Water Lily 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 giant water lily care
In the UK? Keeping giant water 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 giant water lily care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.