Plant care
Chinese Arborvitaetemperature & humidity
Thuja orientalis
More about chinese arborvitae
Ideal temperature for chinese arborvitae
Chinese Arborvitae is comfortable in any room a person is comfortable in, roughly -18°C to 38°C (0°F to 100°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 -18°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Chinese Arborvitae is comparatively hardy (USDA 6–9, 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 chinese arborvitae
Chinese Arborvitae sits happiest at around Low to moderate — 30–65% RH relative humidity. More tolerant of dry air than most Thuja species; performs well in continental and semi-arid climates. Does not require high humidity. Tolerates hot, dry summers better than western North American arborvitaes. Can suffer in cold, wet, poorly drained sites. 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.
Chinese Arborvitae temperature & humidity — frequently asked questions
What temperature is best for chinese arborvitae?
Chinese Arborvitae grows best between -18°C to 38°C (0°F to 100°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 chinese arborvitae tolerate?
Chinese Arborvitae starts to suffer below roughly -18°C. It tolerates a cold dormant period within USDA 6–9, but a wet cold root zone is more dangerous than cold air.
What humidity does chinese arborvitae need?
Chinese Arborvitae prefers about Low to moderate — 30–65% RH relative humidity. More tolerant of dry air than most Thuja species; performs well in continental and semi-arid climates. Does not require high humidity. Tolerates hot, dry summers better than western North American arborvitaes. Can suffer in cold, wet, poorly drained sites.
How do I raise humidity for chinese arborvitae?
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 chinese arborvitae live outside?
Chinese Arborvitae is rated for USDA zone 6–9 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 chinese arborvitae care
In the UK? Keeping chinese arborvitae warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full chinese arborvitae care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.