First, isolate new plants for several weeks until you're sure they're healthy and pest free. Return diseased or pest-ridden plants immediately. Wash your hands thoroughly after touching an infected plant. Discard old plants that are beyond saving.
Clean pots before using them again. Remove all dead leaves and spent blossoms, and clean plants often. Water and mist in the morning. Follow as closely as possible the exact cultural requirements for each plant.
If insects invade a plant, first try washing them away with soapy water. If that doesn't work, use chemical sprays. Spray outside if possible.
Download our Houseplant First Aid chart for specific problem signs, causes, and remedies. (Downloading requires Adobe Acrobat software.)