The leaves of my geraniums are pale and yellowish, and some have bronzy speckles. What is causing this?

The cause is probably spider mites. These are so small you can hardly see them except with a magnifying glass, but they do serious damage to many types of plants. Since these bugs thrive in a dry, hot atmosphere, discourage them by humidifying the air or spraying the plants forcibly with water once or twice a week. But if the infestation is established, you ought to spray every week for three weeks with malathion or some other miticide. Sodium selenate treatment of the soil also cleans up or prevents mites.