Blog Barbara Wagner at www.sanduskyregister.com: "In my new sunroom is a happy plant. My Christmas cactus is growing well and has multitudinous buds on its stems – for the first time in ten years. The simple reason: it now has the right kind of light. And light is a big deal to plants.
Most of us know plants use light in photosynthesis, the process by which light energy is used to form foods from carbon dioxide and water. But, if you are like me, you were not aware that only certain colors of the light spectrum, the red and blue wavelengths, are necessary for photosynthesis to take place.
Natural light provides plants the correct balance of red and blue wavelengths. Though some prefer full sun, 6-8 hours of full exposure a day, and others like shade, the proper wavelengths are available outdoors.
For houseplants, like my Christmas cactus, this is more of a challenge. First most houseplants are tropical in origin. They all need heat to survive and some may also require humidity. They also may need more natural bright light than comes through a window in Ohio winters."