If you get a houseplant as a gift from a friend, put it in an isolated spot for a while and make sure it doesn't carry any disease before you incorporate it into your household greenery. Plant growth may be checked. May be caused by buildup of mold or salt, dry soil, or low humidity. Leach salt from soil by running water through pot. Increase humidity by placing pebbles or marbles and water in a tray under the plant.
Old leaves turn yellow, brown-spotted, dry or curl and drop.
Leaves yellow but remain firm. Caused by overwatering, poor drainage, excessive light, or too much lime in soil or tapwater used to water plants. Remove damaged parts of plant. Use filtered water when watering and replant using acidic potting mix. Can be caused by either over or under watering, shock due to sudden change of light or temperature, mealy bugs, spider mites or scale insects.