Plant care
Fava Beantemperature & humidity
Vicia faba
More about fava bean
Ideal temperature for fava bean
Aim for 5-22°C (41-72°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 5°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Fava Bean is comparatively hardy (USDA Cool-season crop in zones 3-10; autumn-sown and overwintered in milder zones, 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 fava bean
Fava Bean sits happiest at around 40-70% relative humidity. Cool, moderately humid conditions suit it. Good airflow helps prevent chocolate spot and rust, which are worse in damp, crowded stands. 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.
Fava Bean temperature & humidity — frequently asked questions
What temperature is best for fava bean?
Fava Bean grows best between 5-22°C (41-72°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 fava bean tolerate?
Fava Bean starts to suffer below roughly 5°C. It tolerates a cold dormant period within USDA Cool-season crop in zones 3-10; autumn-sown and overwintered in milder zones, but a wet cold root zone is more dangerous than cold air.
What humidity does fava bean need?
Fava Bean prefers about 40-70% relative humidity. Cool, moderately humid conditions suit it. Good airflow helps prevent chocolate spot and rust, which are worse in damp, crowded stands.
How do I raise humidity for fava bean?
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 fava bean live outside?
Fava Bean is rated for USDA zone Cool-season crop in zones 3-10; autumn-sown and overwintered in milder zones 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 fava bean care
In the UK? Keeping fava bean warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full fava bean care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.