Christmas Cactus, Schlumbergeras buckleyi, are abundant and blooming now. There is also a Thanksgiving Cactus, Schlumbergeras truncata which blooms earlier in the holiday season. There are two main differences between a Christmas and Thanksgiving cactus: the flowering season and the segments shape of the leaves. Christmas cacti have smooth, round edges while Thanksgiving cacti have pointy, jagged ones. There is also a third - the holiday Easter cactus, (not included here).
The directions for care for any of these 'tropical cacti' depend on the time of year. After blooming, February - March, they will need a 'rest period' which requires less water and no fertilizing. Let the soil dry out on the surface. If the stems begin to look shriveled, the plant needs a bit more water. Come spring (April - June), begin to increase the water to keep the soil lightly moist, but not wet. Fertilize with a blooming houseplant fertilizer. This is also the time to re pot once established (every 3-5 years) because the roots will need more room to grow and the soil will need 'refreshing'. Summer, (July - August) is the second resting period. Reduce the watering again while keeping in mind that the summer heat will dry out the plant quicker. Keep out of direct sunlight. They like indirect & bright light. That brings us to the holidays, their second active period when they bloom. The water requirements increase. Many liquid fertilize up until bloom. There are two factors which improve blooming: hours of darkness at night and cooler temperatures. In their native habitat, the rain forest of Brazil, night temperatures are around 50-65 and about 12 hours of darkness. That makes our climate well suited for these profuse beauties.
They are quite easy to propagate. Take cuttings of these plants once the flowers are spent. Leaf segments root easily making them easy to share.
from the office of Torrey Pines Landscape