Plant care
Pak Choitemperature & humidity
Brassica rapa subsp. chinensis
More about pak choi
Ideal temperature for pak choi
Temperature kills fewer pak choi 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 13-21°C (55-70°F) is fine; the spot you put the plant in matters more. Below roughly 13°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Pak Choi is comparatively hardy (USDA 2-11 (grown as a cool-season annual; tolerates light frost), RHS H3). 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 pak choi
Pak Choi sits happiest at around Outdoor ambient relative humidity. An outdoor leaf crop with no special humidity requirement, though it appreciates cool, moist air. Hot, dry spells stress plants and trigger premature flowering before the rosette develops. 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.
Pak Choi temperature & humidity — frequently asked questions
What temperature is best for pak choi?
Pak Choi grows best between 13-21°C (55-70°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 pak choi tolerate?
Pak Choi starts to suffer below roughly 13°C. It tolerates a cold dormant period within USDA 2-11 (grown as a cool-season annual; tolerates light frost), but a wet cold root zone is more dangerous than cold air.
What humidity does pak choi need?
Pak Choi prefers about Outdoor ambient relative humidity. An outdoor leaf crop with no special humidity requirement, though it appreciates cool, moist air. Hot, dry spells stress plants and trigger premature flowering before the rosette develops.
How do I raise humidity for pak choi?
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 pak choi live outside?
Pak Choi is rated for USDA zone 2-11 (grown as a cool-season annual; tolerates light frost) and RHS hardiness H3. 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 pak choi care
In the UK? Keeping pak choi warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full pak choi care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.