Plant care
Big Bluestemtemperature & humidity
Andropogon gerardii
More about big bluestem
Ideal temperature for big bluestem
Aim for −34°C to 40°C (−30°F to 104°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 34°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Big Bluestem is comparatively hardy (USDA 4–9, RHS H7). 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 big bluestem
Big Bluestem sits happiest at around 30–70% relative humidity. Adapted to the full range of North American prairie and woodland-edge humidity. Equally at home in the humid East and the drier Great Plains. No humidity modification needed. 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.
Big Bluestem temperature & humidity — frequently asked questions
What temperature is best for big bluestem?
Big Bluestem grows best between −34°C to 40°C (−30°F to 104°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 big bluestem tolerate?
Big Bluestem starts to suffer below roughly 34°C. It tolerates a cold dormant period within USDA 4–9, but a wet cold root zone is more dangerous than cold air.
What humidity does big bluestem need?
Big Bluestem prefers about 30–70% relative humidity. Adapted to the full range of North American prairie and woodland-edge humidity. Equally at home in the humid East and the drier Great Plains. No humidity modification needed.
How do I raise humidity for big bluestem?
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 big bluestem live outside?
Big Bluestem is rated for USDA zone 4–9 and RHS hardiness H7. 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 big bluestem care
In the UK? Keeping big bluestem warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full big bluestem care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.