If your indoor fig tree (Ficus) is starting to drop leaves it may be due to your watering schedule. Don't overwater, and don't let the tree stand in a saucer of water for an extended length of time or its roots may be damaged. On the other hand, don't let soil dry out completely either. Try to keep the soil evenly moist, watering throroughly, then allowing the excess water to drain. Wait until the soil dries out slightly before watering again.