Plant care
Broad Beantemperature & humidity
Vicia faba 'Aquadulce Claudia'
More about broad bean
Ideal temperature for broad 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
Broad Bean is comparatively hardy (USDA 3-8 (cool-season annual; hardy young plants overwinter), 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 broad bean
Broad Bean sits happiest at around Outdoor ambient relative humidity. Outdoor crop unconcerned with humidity, but cool damp conditions encourage chocolate spot. Space plants and weed well to keep air moving. 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.
Broad Bean temperature & humidity — frequently asked questions
What temperature is best for broad bean?
Broad 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 broad bean tolerate?
Broad Bean starts to suffer below roughly 5°C. It tolerates a cold dormant period within USDA 3-8 (cool-season annual; hardy young plants overwinter), but a wet cold root zone is more dangerous than cold air.
What humidity does broad bean need?
Broad Bean prefers about Outdoor ambient relative humidity. Outdoor crop unconcerned with humidity, but cool damp conditions encourage chocolate spot. Space plants and weed well to keep air moving.
How do I raise humidity for broad 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 broad bean live outside?
Broad Bean is rated for USDA zone 3-8 (cool-season annual; hardy young plants overwinter) 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 broad bean care
In the UK? Keeping broad 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 broad bean care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.