Plant care
Wallichiana Ferntemperature & humidity
Dryopteris wallichiana
More about wallichiana fern
Ideal temperature for wallichiana fern
Aim for 10-21°C (50-70°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
Wallichiana Fern is comparatively hardy (USDA 6-9 (cool-hardy; can summer outdoors in shade), 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 wallichiana fern
Wallichiana Fern sits happiest at around 50-70% relative humidity. Appreciates moderate to high humidity; drier indoor air browns the delicate frond margins. A pebble tray or nearby humidifier helps, though it is more forgiving of average room humidity than warm-tropical ferns. 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.
Wallichiana Fern temperature & humidity — frequently asked questions
What temperature is best for wallichiana fern?
Wallichiana Fern grows best between 10-21°C (50-70°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 wallichiana fern tolerate?
Wallichiana Fern starts to suffer below roughly 10°C. It tolerates a cold dormant period within USDA 6-9 (cool-hardy; can summer outdoors in shade), but a wet cold root zone is more dangerous than cold air.
What humidity does wallichiana fern need?
Wallichiana Fern prefers about 50-70% relative humidity. Appreciates moderate to high humidity; drier indoor air browns the delicate frond margins. A pebble tray or nearby humidifier helps, though it is more forgiving of average room humidity than warm-tropical ferns.
How do I raise humidity for wallichiana 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 wallichiana fern live outside?
Wallichiana Fern is rated for USDA zone 6-9 (cool-hardy; can summer outdoors in shade) 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 wallichiana fern care
In the UK? Keeping wallichiana 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 wallichiana fern care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.