Plant care
Freesiatemperature & humidity
Freesia spp. (incl. Freesia corymbosa, Freesia × hybrida)
More about freesia
Ideal temperature for freesia
Aim for 10-21°C (50-70°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 10°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Freesia is comparatively hardy (USDA USDA 9-10 (grown as a tender annual or lifted/forced elsewhere), RHS RHS H2-H3 (half-hardy; tolerates roughly -5 to 1°C, needs frost protection)). 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 freesia
Freesia sits happiest at around 40-60% relative humidity. Average room or greenhouse humidity is fine; freesias are not fussy about moisture in the air. The bigger priority is fresh air movement and good ventilation — stagnant, humid, still conditions encourage Botrytis (grey mould) on the flowers and foliage. During corm storage, by contrast, a high humidity of around 75-80% is recommended. 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.
Freesia temperature & humidity — frequently asked questions
What temperature is best for freesia?
Freesia grows best between 10-21°C (50-70°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 freesia tolerate?
Freesia starts to suffer below roughly 10°C. It tolerates a cold dormant period within USDA USDA 9-10 (grown as a tender annual or lifted/forced elsewhere), but a wet cold root zone is more dangerous than cold air.
What humidity does freesia need?
Freesia prefers about 40-60% relative humidity. Average room or greenhouse humidity is fine; freesias are not fussy about moisture in the air. The bigger priority is fresh air movement and good ventilation — stagnant, humid, still conditions encourage Botrytis (grey mould) on the flowers and foliage. During corm storage, by contrast, a high humidity of around 75-80% is recommended.
How do I raise humidity for freesia?
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 freesia live outside?
Freesia is rated for USDA zone USDA 9-10 (grown as a tender annual or lifted/forced elsewhere) and RHS hardiness RHS H2-H3 (half-hardy; tolerates roughly -5 to 1°C, needs frost protection). 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 freesia care
In the UK? Keeping freesia warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full freesia care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.