Like many houseplants, the ficus is really a warm-weather 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 weather. But just bringing your ficus indoors when the temperature drops might not be enough to guarantee a healthy plant. The goal with wintering a ficus isn't growth so much as it is survival. Ideally you should be able to minimize leaf loss and send the plant into a kind of suspended animation throughout the winter.
Here are some tips to overwinter a ficus plant indoors.
Start Out With a Healthy Ficus
This tip might seem obvious, but it's not something to overlook. Going into winter with a healthy ficus will significantly increase the plant's chances of making it through alive and well. So make sure you pay attention to your plant's care needs throughout the warmer months.
It should have rich soil with good drainage. It needs even soil moisture but not overwatering to the point of soggy soil. And it benefits from monthly fertilization in the spring and summer, backing off to fertilization every other month in the fall and winter. Moreover, when moving a plant from outside to inside, make sure to check the foliage and the pot for any signs of bugs or diseases, such as eaten or discolored foliage. Treat any issues as soon as possible, and quarantine the plant from your other houseplants.
Choose the Right Indoor Location
When choosing where in your home to keep your ficus for the winter, look for a place that gets lots of sunlight. You want to saturate the plant with as much light as possible. Ficus are full-sun trees in their native habitats, meaning they prefer at least six hours a day of direct sunlight. It's a good idea to rotate your ficus a quarter turn or so at least weekly, so different parts of the plant face the light from the window. That way, the plant will continue to grow evenly. If natural light is hard to find indoors, you can place a small plant growing lamp over your ficus. Just remember to turn off the lamp at night to simulate the cycle of night and day.
Moreover, don't expose your ficus to drafts. This includes cold drafts from windows and doors, as well as hot, dry air from heating vents. These extreme temperature fluctuations can weaken and damage the plant. In fact, the dry air in particular can cause leaves to dry up and drop off the plant.
Take Steps to Prevent 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 and the air gets dry. This is a natural way for your plant to conserve energy.
It might seem counterintuitive, but you actually should 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 rainy and dry seasons. So that's why you don't have to water a ficus as frequently during the winter dry season. However, even in the dry season, the tropics are still humid. So maintaining humid conditions for your ficus—either through misting the plant every other day or adding a small humidifier to its room—will help to keep it healthy and minimize leaf loss.
Then, when the weather starts to warm back up and the daylight hours increase, go back to spoiling your ficus with more regular watering and feeding. Also, this is the time to repot it if its roots are too tightly bound in its existing pot. This will ultimately help to perk up the foliage and maintain as many healthy leaves as possible.