Plant care
Nasturtium officinaletemperature & humidity
Nasturtium officinale
More about nasturtium officinale
Ideal temperature for nasturtium officinale
Nasturtium officinale is comfortable in any room a person is comfortable in, roughly 10-22°C (50-72°F). 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 10°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Nasturtium officinale is comparatively hardy (USDA 5-11 (a cool-season hardy perennial that overwinters in mild areas and is grown as an annual where streams freeze), RHS H5). 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 nasturtium officinale
Nasturtium officinale sits happiest at around 50-90% relative humidity. Likes high ambient and root-zone moisture but is forgiving of average indoor air as long as the roots stay wet and cool. The real driver of success is constant water at the roots, not air humidity. 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.
Nasturtium officinale temperature & humidity — frequently asked questions
What temperature is best for nasturtium officinale?
Nasturtium officinale grows best between 10-22°C (50-72°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 nasturtium officinale tolerate?
Nasturtium officinale starts to suffer below roughly 10°C. It tolerates a cold dormant period within USDA 5-11 (a cool-season hardy perennial that overwinters in mild areas and is grown as an annual where streams freeze), but a wet cold root zone is more dangerous than cold air.
What humidity does nasturtium officinale need?
Nasturtium officinale prefers about 50-90% relative humidity. Likes high ambient and root-zone moisture but is forgiving of average indoor air as long as the roots stay wet and cool. The real driver of success is constant water at the roots, not air humidity.
How do I raise humidity for nasturtium officinale?
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 nasturtium officinale live outside?
Nasturtium officinale is rated for USDA zone 5-11 (a cool-season hardy perennial that overwinters in mild areas and is grown as an annual where streams freeze) and RHS hardiness H5. 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 nasturtium officinale care
In the UK? Keeping nasturtium officinale warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full nasturtium officinale care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.