The bright window spot chosen for houseplants to receive maximum sunlight can become one of the coldest places in the house in winter. The glass itself can get cold, and with heavy curtains drawn, it creates a cooler box area around the window. For tropical plants like anthuriums and philodendrons, which are used to less temperature fluctuation, the cold can be fatal.
The hack and method
Move sensitive plants back from the glass overnight, then return them to their brighter position in the morning.
Start by using a thermometer to check how cold the windowsill actually gets. If you don't have heavy curtains, keep leaves from touching the glass; if you do, move the plants from the windowsill into the room overnight.
The test and verdict
During winter, some plants were left on a south-facing windowsill and others were moved into the room. In a centrally heated home with double-glazed windows, in rooms where the heating is not used, the windowsill temperature dropped to around 15C overnight. The more delicate tropicals were happier away from the cold windowsill, while hardier cacti were happy to stay put. Less leaf damage was also seen by not letting foliage touch the cold glass.
If you have draughty glazing and tropical plants, it is worth the shuffle. Sometimes good winter care really is as simple as moving a pot.
