Ficus trees grow as both indoor potted trees and outdoors during the warm months of summer. There are many varieties of ficus, including the fruit-producing fig tree. The rubber tree and weeping fig are two ficus varieties that are commonly grown as houseplants. Ficus require regular fertilization, otherwise the leaves tend to yellow and drop off. The plant also becomes more susceptible to other stress problems, such as drought or insects, when it is not fed regularly.
Fertilize ficus when it is actively growing and producing new leaves. For most varieties, this occurs from spring until fall.
Feed ficus every four weeks with a general-purpose, water-soluble houseplant fertilizer. Apply the fertilizer at half the rate recommended on the label.
Water the ficus immediately after fertilizing, so that excess salts from the fertilizer are flushed form the soil. Immediate watering also forces the fertilizer down to the root zone of the plant. Water from the top of the pot until the excess moisture drains from the bottom. Soil that has collected too much fertilizer salt may form a white crust on top the soil in the pot.