Plant care
Crested Floating Hearttemperature & humidity
Nymphoides cristata
More about crested floating heart
Ideal temperature for crested floating heart
Aim for 18–32°C (64–90°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 18°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Crested Floating Heart is frost-tender (USDA 8-11, 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 crested floating heart
Crested Floating Heart sits happiest at around High (water surface environment) relative humidity. As a floating-leaf aquatic, the plant is naturally surrounded by high surface humidity. No supplemental humidity management is needed. In indoor tub gardens near sunny windows, ensure the water surface temperature does not exceed 32°C (90°F), as overheating stresses the plant. 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.
Crested Floating Heart temperature & humidity — frequently asked questions
What temperature is best for crested floating heart?
Crested Floating Heart grows best between 18–32°C (64–90°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 crested floating heart tolerate?
Crested Floating Heart starts to suffer below roughly 18°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 crested floating heart need?
Crested Floating Heart prefers about High (water surface environment) relative humidity. As a floating-leaf aquatic, the plant is naturally surrounded by high surface humidity. No supplemental humidity management is needed. In indoor tub gardens near sunny windows, ensure the water surface temperature does not exceed 32°C (90°F), as overheating stresses the plant.
How do I raise humidity for crested floating heart?
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 crested floating heart live outside?
Crested Floating Heart is rated for USDA zone 8-11 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 crested floating heart care
In the UK? Keeping crested floating heart warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full crested floating heart care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.