Provide cool conditions for certain plants
Keep in mind that most houseplants are happy with the warm air temperatures during the day and lower ones, such as 18°C, at night. For plants that prefer cool winter conditions (gardenias, cyclamen and most cacti, for example), seek out a room that you keep cooler than others but still above freezing—a spare bedroom, perhaps. Keep all plants out of cold drafts and blasts of heat.
Dealing with a lack of daylight
Winter days are short and, in many areas, cloudy. Even on a sunny January day, plants may get less light than they need and will live on the reserves of photosynthetic energy they've stored up over the summer. Some plants—such as philodendrons, Chinese evergreens (Aglaonema cvs.) and dracaenas—can live for months on these reserves but others show telltale signs of weak, leggy growth, or experience leaf loss or even death if they don't recharge daily.
Find the bright spots
The most obvious solution is to move plants to a brighter location. Big windows let in more light than small ones, and plants placed close to (but not touching) glass will also get more light. The sunny, south-facing window that was too hot for plants in summer can be a haven for them in winter. Rooms with light coming from two or more directions are a godsend, as are, of course, the ultimate houseplant winter havens: solariums and greenhouses. Be wary of north-facing windows, basement windows or any location far from a window. Although they may seem bright enough, they can rarely support much plant growth in winter.
Try using pale colours when decorating around plants. Pale colours reflect light, which plants can use. Forget plum walls and mahogany furniture: they absorb light.
Image: An unnamed Phalaenopsis orchid cultivar. Photography by Anne Gordon.