These plants are members of the cactus family, but are native to moist, tropical forests. The Christmas cactus (Schlumbergera bridgesii) is the most common variety. Commercial growers are able to force these plants into bloom for the Christmas season. However, timing this bloom is difficult for the home gardener. These plants are long-lived and will survive in the home for years.
Like almost all flowering plants, Christmas cactus require bright light. Avoid direct sun. A west, east, or shaded south window is ideal.
During their rest period, form early September until their buds are set, and during winter after flowering, allow plants to dry out slightly between waterings. The rest of the year, especially while in bud, the plant prefers to stay moist.
During most of the year, average household temperatures are fine for Christmas cactus.
Short days and cool night temperatures (45-55 F) are necessary to induce flower bud set. Keep the plants outdoors in the light shade when there is no danger of frost. When frost threatens, place the plant where it will get the necessary light to keep it healthy. Give the plant at least 13 hours of uninterrupted darkness each night. Once buds are visible, this treatment is no l onger needed. Move the plant to a spot where you can enjoy the bloom.
Fertilize with a water soluble house plant food during periods of growth and bloom. Do not feed during rest periods. A high phosphorus formulation just prior to the rest period will help improve bloom set and size.
New plants can be started easily from stem tip cuttings. Break off short Y-shaped sections of stem and pot them in a very porous, well-drained potting mix. Keep the soil moist, but not wet. When roots have formed, in 4-6 weeks, pot each new plant individually.