The healthy selloum temperature range sits between 70 and 80 degrees Fahrenheit (21 to 27°C). Move the plant somewhere warmer once nights drop below 60 degrees Fahrenheit (16°C). Push past that low end and the leaves start to suffer fast. This plant comes from warm regions, so it has no real defense against a hard chill. Keep it in that warm band and it grows steadily all year.
You can see the damage with your own eyes after one bad night. Picture a selloum left by a cold drafty window or out on an unheated porch in winter. Within a day or two it shows blackened, mushy leaf edges. The first real cold snap is the true test of where you keep it. Warm afternoons fool a lot of people. The plant cares about how low the nights go, not how nice the day felt.
Age and size make a big difference here. A young plant with thin stems can die outright from a chill that an old specimen shrugs off. Mature plants build a thick, woody stem over the years. That stem usually survives a light freeze even when the leaves get burned. UF/IFAS and LSU both note this gap. So an old selloum can look ruined after frost and still push out fresh new growth once the warmth returns. Give it time before you decide it is gone.
The cold tolerance of this plant has a clear floor. Brief dips near freezing scorch the foliage. A true hard freeze can kill it down to the roots. NC State puts the move-indoors line at 60 degrees Fahrenheit (16°C) for potted plants. That number gives you a safe buffer before any harm starts. Treat it as your alarm, not the plant's limit. Acting at 60 buys you room when a forecast turns out colder than promised.
Where you live decides whether it can stay outside all year. This plant grows outdoors in roughly USDA zones 8 to 11, though the exact call depends on your source. NC State lists zones 9a to 11b. LSU lists zones 8 to 10. So the safe read is the 8 to 11 range. In zone 8 you take a real risk during a cold winter. Many growers there keep one in a pot they can carry inside. That way they enjoy the big tropical leaves without gambling on the weather.
A few habits keep your plant out of the danger zone. Set it away from cold drafts near doors and single-pane windows in winter. Keep it clear of heat vents too. Dry blasting air dries out the leaves and stresses the roots. For potted plants, bring them inside before nights fall below 60 degrees Fahrenheit (16°C). Do it a day early rather than a day late, since one missed night can undo a whole season of growth.
Match your care to your climate and this plant stays easy. Indoors, hold it in that 70 to 80 degree sweet spot and skip the cold corners. Outdoors, plant it in the ground only if you sit in zones 9 through 11. Use a pot you can move if you are in zone 8. Get the temperature right and the rest of the care falls into place. Light, water, and feeding all matter less than keeping this warm-blooded plant out of the cold. Stay inside the selloum temperature range and you will rarely see a damaged leaf. The winter outside can be as rough as it wants.
Read the full article: Philodendron Selloum Care Guide
