why are the leaves on my christmas cactus turning red

The leaves of your Christmas cactus turning red is a natural response to the shorter days and cooler temperatures of fall and winter. As the days grow shorter and the nights grow longer, the Christmas cactus is preparing for its winter rest. It is producing pigments called anthocyanins, which give the leaves their red color. These pigments are produced in response to the reduced levels of light and cooler temperatures, helping to protect the plant from the cold. So, there's no need to worry, it's just a natural part of the plant's seasonal cycle.