Plant care
Alpine Mouse-eartemperature & humidity
Cerastium alpinum
More about alpine mouse-ear
Ideal temperature for alpine mouse-ear
Aim for -40 to 18°C (-40 to 64°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 -40°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Alpine Mouse-ear is comparatively hardy (USDA 2–6, RHS H7). 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 alpine mouse-ear
Alpine Mouse-ear sits happiest at around Low (20–45% RH) relative humidity. Adapted to cold, dry mountain air. High humidity at mild temperatures promotes botrytis and rot. In cultivation, an alpine house or unheated cold frame provides the dry overhead conditions the plant needs in winter. 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.
Alpine Mouse-ear temperature & humidity — frequently asked questions
What temperature is best for alpine mouse-ear?
Alpine Mouse-ear grows best between -40 to 18°C (-40 to 64°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 alpine mouse-ear tolerate?
Alpine Mouse-ear starts to suffer below roughly -40°C. It tolerates a cold dormant period within USDA 2–6, but a wet cold root zone is more dangerous than cold air.
What humidity does alpine mouse-ear need?
Alpine Mouse-ear prefers about Low (20–45% RH) relative humidity. Adapted to cold, dry mountain air. High humidity at mild temperatures promotes botrytis and rot. In cultivation, an alpine house or unheated cold frame provides the dry overhead conditions the plant needs in winter.
How do I raise humidity for alpine mouse-ear?
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 alpine mouse-ear live outside?
Alpine Mouse-ear is rated for USDA zone 2–6 and RHS hardiness H7. 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 alpine mouse-ear care
In the UK? Keeping alpine mouse-ear warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full alpine mouse-ear care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.