Plant care
Winter Marjoramtemperature & humidity
Origanum heracleoticum
More about winter marjoram
Ideal temperature for winter marjoram
Winter Marjoram is comfortable in any room a person is comfortable in, roughly 15–30°C (59–86°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 15°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Winter Marjoram is comparatively hardy (USDA 5-9, 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 winter marjoram
Winter Marjoram sits happiest at around 30–50% relative humidity. Thrives in low to moderate humidity. Good air circulation is more important than specific humidity levels. High humidity combined with wet soil creates ideal conditions for root and crown rots. Avoid enclosed, still environments indoors. 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.
Winter Marjoram temperature & humidity — frequently asked questions
What temperature is best for winter marjoram?
Winter Marjoram grows best between 15–30°C (59–86°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 winter marjoram tolerate?
Winter Marjoram starts to suffer below roughly 15°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 winter marjoram need?
Winter Marjoram prefers about 30–50% relative humidity. Thrives in low to moderate humidity. Good air circulation is more important than specific humidity levels. High humidity combined with wet soil creates ideal conditions for root and crown rots. Avoid enclosed, still environments indoors.
How do I raise humidity for winter marjoram?
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 winter marjoram live outside?
Winter Marjoram is rated for USDA zone 5-9 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 winter marjoram care
In the UK? Keeping winter marjoram warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full winter marjoram care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.