Plant care
Hound's Tongue Ferntemperature & humidity
Microsorum pustulatum
More about hound's tongue fern
Ideal temperature for hound's tongue fern
Hound's Tongue Fern is comfortable in any room a person is comfortable in, roughly 16-26°C (60-78°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 16°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Hound's Tongue Fern is frost-tender (USDA 9-11, RHS H2). It cannot survive a frost, so in most of the US and UK it lives indoors year-round or summers outside and comes back in well before the first autumn frost — once nights drop toward 10-12°C is the cue, not the first frost warning. Acclimate it over a week when moving between indoors and out so the leaves do not shock.
Humidity for hound's tongue fern
Hound's Tongue Fern sits happiest at around 40-65% relative humidity. More tolerant of average household humidity than most ferns; 40-50% is manageable, though 55-65% gives best growth and glossiest fronds. A pebble tray or occasional misting helps in centrally heated rooms. Avoid consistently dry air below 35%, which causes tip browning. 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.
Hound's Tongue Fern temperature & humidity — frequently asked questions
What temperature is best for hound's tongue fern?
Hound's Tongue Fern grows best between 16-26°C (60-78°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 hound's tongue fern tolerate?
Hound's Tongue Fern starts to suffer below roughly 16°C. It is frost-tender and will be damaged or killed by a frost, so bring it indoors once nights fall toward 10-12°C.
What humidity does hound's tongue fern need?
Hound's Tongue Fern prefers about 40-65% relative humidity. More tolerant of average household humidity than most ferns; 40-50% is manageable, though 55-65% gives best growth and glossiest fronds. A pebble tray or occasional misting helps in centrally heated rooms. Avoid consistently dry air below 35%, which causes tip browning.
How do I raise humidity for hound's tongue 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 hound's tongue fern live outside?
Hound's Tongue Fern is rated for USDA zone 9-11 and RHS hardiness H2. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More hound's tongue fern care
In the UK? Keeping hound's tongue 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 hound's tongue fern care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.