Plant care
Olympic St. John's Worttemperature & humidity
Hypericum olympicum
More about olympic st. john's wort
Ideal temperature for olympic st. john's wort
Temperature kills fewer olympic st. john's wort plants than you'd think. What kills them is the micro-climate within a normal-temperature room — a leaf pressed against single-glazed winter glass, the hot dry updraft directly above a radiator, the cold blast from an AC vent. The thermostat reading at -20 to 35°C (-4 to 95°F) is fine; the spot you put the plant in matters more. Below roughly -20°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Olympic St. John's Wort is comparatively hardy (USDA 5–9, RHS H6). 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 olympic st. john's wort
Olympic St. John's Wort sits happiest at around 30–60% relative humidity. Adapted to the dry, breezy conditions of exposed Balkan mountain slopes. Prefers low to moderate humidity. In high-humidity maritime climates, ensure excellent drainage and strong air circulation; avoid crowding with other plants. 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.
Olympic St. John's Wort temperature & humidity — frequently asked questions
What temperature is best for olympic st. john's wort?
Olympic St. John's Wort grows best between -20 to 35°C (-4 to 95°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 olympic st. john's wort tolerate?
Olympic St. John's Wort starts to suffer below roughly -20°C. It tolerates a cold dormant period within USDA 5–9, but a wet cold root zone is more dangerous than cold air.
What humidity does olympic st. john's wort need?
Olympic St. John's Wort prefers about 30–60% relative humidity. Adapted to the dry, breezy conditions of exposed Balkan mountain slopes. Prefers low to moderate humidity. In high-humidity maritime climates, ensure excellent drainage and strong air circulation; avoid crowding with other plants.
How do I raise humidity for olympic st. john's wort?
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 olympic st. john's wort live outside?
Olympic St. John's Wort is rated for USDA zone 5–9 and RHS hardiness H6. 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 olympic st. john's wort care
In the UK? Keeping olympic st. john's wort warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full olympic st. john's wort care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.