Like so many houseplants, the ficus is really a summer plant. It is native to tropical and subtropical regions, so while a ficus might be able to handle a little nip in the air, it can't withstand true winter. Just bringing your ficus in when the temperature drops might not be enough to guarantee a healthy plant. The idea with wintering a ficus isn't growth, as much as it is survival. Ideally, you can minimize leaf loss and send the plant into a kind of suspended animation throughout the winter.
Follow these tips to overwinter your ficus indoors.
Start Out Healthy
Of course, it seems obvious, but going into winter healthy will significantly increase the plant's chances of making it through alive. A well-fed, vibrant plant has a much higher chance of surviving. If the plant is outside, this also means making sure it's bug-free before moving it back inside.
Indoor Location Tips for Ficus
When choosing where in your home to store your plant for the winter, look for a place that gets lots of sunlight and is away from drafts. You want to saturate it with as much light as possible. Ficus are full-sun trees in their native habitats, so give it good, strong winter sun. If natural light is hard to find, you can substitute a small plant growing lamp. Just remember to turn the lamp off at night to simulate the effect of night and day.
Don't expose your plant to drafts. This includes cold drafts from windows as well as hot, dry air from radiator vents.
The bone-dry air will cause more leaves to fall. It's also a good idea to rotate your ficus weekly. Give it a quarter turn or so, to allow the plant to get an even amount of sunlight on all the leaves.
How to Handle Leaf-Drop
Leaf-drop is common throughout the winter months, but the wrong thing to do is respond with a deluge of water.
Don't overreact. You're going to lose some leaves as the temperature drops. This is a natural way for your plant to conserve energy. It may seem counter-intuitive, but you actually want to water your plant less in the winter. What your ficus really needs is more humidity.
The ficus plant comes from areas with distinct seasons, but instead of hot and cold, they are used to rainy and dry seasons. So don't worry about cutting back water during the winter. At most you should water them biweekly, but you can water them even less frequently, and they'll be ok. However, even in the "dry" season, the tropics are still humid. If you have a humidifier, your ficus will love it. If not, mist the plant two or three mornings a week.
When it starts to warm back up, and the daylight hours increase, don't hesitate to spoil your ficus again as a reward: feed it, repot if necessary, and increase watering. Remember, a healthy winter begins in the summer.