Plant care
'Red Russian' Kaletemperature & humidity
Brassica napus var. pabularia 'Red Russian'
More about 'red russian' kale
Ideal temperature for 'red russian' kale
Aim for 7-24°C (45-75°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 7°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
'Red Russian' Kale is comparatively hardy (USDA 3-9 (very cold-hardy; survives hard frosts and light snow), 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 'red russian' kale
'Red Russian' Kale sits happiest at around Outdoor ambient relative humidity. A hardy outdoor leaf crop needing no special humidity. Cool, moist air suits it; frost deepens the red coloration and sweetens the flavour. 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.
'Red Russian' Kale temperature & humidity — frequently asked questions
What temperature is best for 'red russian' kale?
'Red Russian' Kale grows best between 7-24°C (45-75°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 'red russian' kale tolerate?
'Red Russian' Kale starts to suffer below roughly 7°C. It tolerates a cold dormant period within USDA 3-9 (very cold-hardy; survives hard frosts and light snow), but a wet cold root zone is more dangerous than cold air.
What humidity does 'red russian' kale need?
'Red Russian' Kale prefers about Outdoor ambient relative humidity. A hardy outdoor leaf crop needing no special humidity. Cool, moist air suits it; frost deepens the red coloration and sweetens the flavour.
How do I raise humidity for 'red russian' kale?
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 'red russian' kale live outside?
'Red Russian' Kale is rated for USDA zone 3-9 (very cold-hardy; survives hard frosts and light snow) 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 'red russian' kale care
In the UK? Keeping 'red russian' kale warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full 'red russian' kale care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.