Plant care
Chain Ferntemperature & humidity
Woodwardia radicans
More about chain fern
Ideal temperature for chain fern
Aim for 5-26°C (41-79°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 5°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Chain Fern is comparatively hardy (USDA 8-10, RHS H4). 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 chain fern
Chain Fern sits happiest at around 60-80% relative humidity. A subtropical-looking fern that loves moist, sheltered air. High humidity keeps the large fronds lush; dry, exposed sites cause browning and tattering. 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.
Chain Fern temperature & humidity — frequently asked questions
What temperature is best for chain fern?
Chain Fern grows best between 5-26°C (41-79°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 chain fern tolerate?
Chain Fern starts to suffer below roughly 5°C. It tolerates a cold dormant period within USDA 8-10, but a wet cold root zone is more dangerous than cold air.
What humidity does chain fern need?
Chain Fern prefers about 60-80% relative humidity. A subtropical-looking fern that loves moist, sheltered air. High humidity keeps the large fronds lush; dry, exposed sites cause browning and tattering.
How do I raise humidity for chain fern?
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 chain fern live outside?
Chain Fern is rated for USDA zone 8-10 and RHS hardiness H4. 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 chain fern care
In the UK? Keeping chain fern warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full chain fern care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.