Plant care
Celerytemperature & humidity
Apium graveolens
More about celery
Ideal temperature for celery
Aim for 10 to 24°C (50 to 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 growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Celery is comparatively hardy (USDA 2-10, 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 celery
Celery sits happiest at around 60–80% relative humidity. Prefers higher humidity as suited to its native moist-meadow habitat. In dry air, leaf edges may scorch and stalks can become tough. Mulching around the base conserves soil moisture and reduces temperature fluctuation, indirectly supporting the humid root environment celery prefers. 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.
Celery temperature & humidity — frequently asked questions
What temperature is best for celery?
Celery grows best between 10 to 24°C (50 to 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 celery tolerate?
Celery starts to suffer below roughly 10°C. It tolerates a cold dormant period within USDA 2-10, but a wet cold root zone is more dangerous than cold air.
What humidity does celery need?
Celery prefers about 60–80% relative humidity. Prefers higher humidity as suited to its native moist-meadow habitat. In dry air, leaf edges may scorch and stalks can become tough. Mulching around the base conserves soil moisture and reduces temperature fluctuation, indirectly supporting the humid root environment celery prefers.
How do I raise humidity for celery?
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 celery live outside?
Celery is rated for USDA zone 2-10 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 celery care
In the UK? Keeping celery warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full celery care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.