There's a good reason why another name for a ficus tree is "weeping fig." That's because if you own one, sooner or later it's going to make you cry.
The scenario goes like this. You go to bed with your healthy-looking ficus tree sitting happily in the living room. You wake up to find half of its leaves sitting miserably on the floor.
Because out of all the houseplants you could have picked, weeping fig (Ficus benjamina) is probably the most finicky. The question is not if it will drop leaves. The question is when?
Here is a list of common reasons a ficus tree drops its leaves.
1. You bought it at a greenhouse and brought it home. See, a ficus tree hates change. And in your house, it finds dimmer light and lower humidity than in the greenhouse. It also misses that hot, new ficus that was sitting next to it. Could have been some possibilities there. So in a fit of pique, it drops leaves.
2. You kept it in one room for a while and then you moved it somewhere else. Didn't I tell you this plant hates change? It noticed the different light and temperature. And it's still mad from being abducted from the greenhouse. Result? Dropped leaves.
3. You let it dry out. This plant likes moist soil that drains well. If the soil gets too dry, it drops leaves, usually while they're still green.
4. You overwatered it. When this happens, the leaves often fall off yellow like those above.
Solving the Problem The easiest solution to a sickly ficus tree like this is to throw it out and replace it with one of its easy-to-grow relatives, like fiddleleaf fig (Ficus lyrata), rubber plant (Ficus elastica), or "Alii' banana leaf fig (Ficus maclellandii 'Alii'). These plants are carefree, happy campers. And they're all readily available.
But if you're determined to keep weeping fig as a houseplant, cater to its whims. Give it bright, indirect light -- no hot sun. Don't let the temperature drop below 60 degrees. Keep it out of wind and cold drafts. Keep the soil moist, but not soggy. Mist the foliage to raise humidity. Don't move it from room to room -- find a place where it can live undisturbed.
Falling leaves don't mean the plant will die. If you meet its requirements and give it time to adjust to a new location, new growth will follow. But don't cry when you see a couple of fallen leaves on the floor beneath it practically every day. Hey, that's just what it does.