Fertilizing a Christmas cactus during the winter months can be tricky, as it requires some careful consideration. While most plants benefit from regular fertilizing during their growing season, cacti and succulents are different. They are adapted to store nutrients and moisture in their thick leaves, and over-fertilizing can cause them to burn or become waterlogged.
If you want to fertilize your Christmas cactus during the winter, it's best to do so in moderation and only when the soil has completely dried out. You can use a specialized cactus fertilizer, which is usually lower in nitrogen and higher in phosphorus and potassium,