Plant care
Geranium sanguineum var. striatumtemperature & humidity
Geranium sanguineum var. striatum
More about geranium sanguineum var. striatum
Ideal temperature for geranium sanguineum var. striatum
Aim for -25 to 27°C (-13 to 80°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 -25°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Geranium sanguineum var. striatum is comparatively hardy (USDA 3-8 (outdoor hardy perennial), 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 geranium sanguineum var. striatum
Geranium sanguineum var. striatum sits happiest at around 40-70% relative humidity. An outdoor hardy perennial unconcerned by humidity; prefers dry air and open airflow that suppress mildew. No humidity management required. 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.
Geranium sanguineum var. striatum temperature & humidity — frequently asked questions
What temperature is best for geranium sanguineum var. striatum?
Geranium sanguineum var. striatum grows best between -25 to 27°C (-13 to 80°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 geranium sanguineum var. striatum tolerate?
Geranium sanguineum var. striatum starts to suffer below roughly -25°C. It tolerates a cold dormant period within USDA 3-8 (outdoor hardy perennial), but a wet cold root zone is more dangerous than cold air.
What humidity does geranium sanguineum var. striatum need?
Geranium sanguineum var. striatum prefers about 40-70% relative humidity. An outdoor hardy perennial unconcerned by humidity; prefers dry air and open airflow that suppress mildew. No humidity management required.
How do I raise humidity for geranium sanguineum var. striatum?
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 geranium sanguineum var. striatum live outside?
Geranium sanguineum var. striatum is rated for USDA zone 3-8 (outdoor hardy perennial) 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 geranium sanguineum var. striatum care
In the UK? Keeping geranium sanguineum var. striatum warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full geranium sanguineum var. striatum care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.