Plant care
Philodendron Imperial Redtemperature & humidity
Philodendron erubescens 'Imperial Red'
More about philodendron imperial red
Ideal temperature for philodendron imperial red
Temperature kills fewer philodendron imperial red plants than you'd think. What kills them is the micro-climate within a normal-temperature room — a leaf pressed against single-glazed winter glass, the hot dry updraft directly above a radiator, the cold blast from an AC vent. The thermostat reading at 18-29C (65-85F) is fine; the spot you put the plant in matters more. Below roughly 18°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Philodendron Imperial Red is comparatively hardy (USDA 9b-11 (outdoors); grown as a houseplant elsewhere, RHS undefined). 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 philodendron imperial red
Philodendron Imperial Red sits happiest at around 40-60% relative humidity. Adapts well to average household humidity but prefers higher levels, which support larger, glossier leaves. In dry rooms or winter heating, group plants, use a pebble tray, or run a humidifier. Browning leaf edges often signal that the air is too dry. 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.
Philodendron Imperial Red temperature & humidity — frequently asked questions
What temperature is best for philodendron imperial red?
Philodendron Imperial Red grows best between 18-29C (65-85F). 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 philodendron imperial red tolerate?
Philodendron Imperial Red starts to suffer below roughly 18°C. It tolerates a cold dormant period within USDA 9b-11 (outdoors); grown as a houseplant elsewhere, but a wet cold root zone is more dangerous than cold air.
What humidity does philodendron imperial red need?
Philodendron Imperial Red prefers about 40-60% relative humidity. Adapts well to average household humidity but prefers higher levels, which support larger, glossier leaves. In dry rooms or winter heating, group plants, use a pebble tray, or run a humidifier. Browning leaf edges often signal that the air is too dry.
How do I raise humidity for philodendron imperial red?
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 philodendron imperial red live outside?
Philodendron Imperial Red is rated for USDA zone 9b-11 (outdoors); grown as a houseplant elsewhere. 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 philodendron imperial red care
In the UK? Keeping philodendron imperial red warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full philodendron imperial red care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.