Houseplants have a lot to offer a home, providing lively ornamental value in bare spaces for a fraction of the cost of a new piece of furniture. Just like plants in the garden, houseplants are subject to a number of problems that are unique to their living environment.
If your houseplant has yellowing leaves, brown-tipped leaves or is simply wilting away, the problem may be root rot. Root rot is an extremely common problem with houseplants; it is usually caused by overwatering. To check if your plant has root rot, carefully take the plant out of its pot or container and check the roots. If they look white and clean (save for the dirt), then the problem lies elsewhere, but if the roots are slimey and have black or brown decay, then the plant is suffering from root rot. Root rot can be prevented by planting houseplants in a well-draining soil in a container that has a hole in the bottom for drainage. Water the plant only when the soil is almost completely dry.
Fungus causes unattractive spots on a plant's foliage; these spots may cause leaves to eventually wither and fall off the plant. The spots may vary in color, although they are often black dots that vary in size from small pinpricks to irregular blotches. Fungus is caused by overcrowding of plants, or from water getting on the foliage. Treat fungus by moving the plant to a well-ventilated area and picking off infected leaves. Always keep a plant infected by fungus away from healthy plants, as it may spread. Prevent the problem by taking extra care not to get water on the plants. Avoid misting a plant if fungus has been a problem.
Pests often appear as small, moving, white or green patches on the underside of a plant's leaves, or on new growth. Aphids, mealybugs and mites are all common houseplant pests. Though pesticides may be used, there are safer methods of removing common pests. Mild infections can be treated by spraying the plant with a strong steam of water. If water isn't strong enough, try heavily diluting castille soap or rubbing alcohol and gently washing the plant's leaves. Be sure to gently dry the foliage off after spraying with water to prevent fungal infections. Pluck off leaves or flowers that are heavily infected if necessary.