A healthy dieffenbachia plant boasts green and cream leaves. A dieffenbachia with yellow leaves denotes a problem, and you need to do something different for its care. Make sure that it's watered regularly, give it plant food, inspect it for pest infestation, and place it in a shady area.
Water it regularly
Water your dieffenbachia regularly. It needs plenty of water to thrive. Its leaves turn yellow as a signal of insufficient water. Make sure the soil remains moist. If your plant is struggling, increase the humidity of its environment by placing a tray with water under the plant.
Because inadequate nutrition can result in yellowing foliage, feed your dieffenbachia plant food. Follow the instructions on the label of the plant food container, and feed the plant monthly.
Inspect it for infestation
Inspect your dieffenbachia for pest infestation. Spider mites especially like to feed on the leaves, leaving the foliage yellowed and deformed. Spray away any mites with water, and use cooled coffee as an insecticide.
Place it in a good location
Place your dieffenbachia in a shady location. Too much sun can hurt the plant, yellowing and curling its leaves. Make sure it doesn't get direct sunlight.