Schlumbergera flowers are sensitive to excess heat, exposure to ethylene gas, and lack of light. In response to one or more of these conditions, buds drop off rather than drying up, as they would on some other stressed flowering plants. Damage may also occur shortly after the schlumbergera is moved.
Avoid exposing schlumbergera to excessive warmth when the plant is about to bloom. 40° to 70°F at night and 60° to 80°F by day should work. Daytime temperatures below 60°F, delay flowering. Keep the plant away from fireplaces, gas heaters and heating vents, and ripening fruit. Insufficient light can also cause bud drop. Bright light with at least some morning sun is usually necessary to prevent loss of buds. Don''t move the plant after it has budded.
In the wild, Christmas cactus rely on lengthening nights and cooler night temperatures to begin blooming. They will not bloom if nights are shorter than 13 hours and warmer than 55°F. Since most people only turn their house lights off for 8 hours a night, and most homes are warmer than 55°, Christmas cactus will not bloom indoors unless given special treatment. In nature, Christmas cactus blooms in November or December, depending on the species. A related plant, Easter cactus (Rhipsalidopsis), blooms in mid-spring.
In fall, this plant needs either long or cool nights. An unheated room that can be left dark at night is ideal. If your climate permits, place the plant on a covered porch, but don''t leave it out if frost threatens. Nights longer than 13 hours or cooler than 55° will trigger blooming; plants don''t require both. The dark must be unbroken. Even a short period of light keeps the night from being long enough. The plant will bloom about 6 weeks from the beginning of this treatment.
This plant disease is caused by any of several fungi, including those known as water molds. These soil-inhabiting fungi (Phythium and Phytophthora species) spread through the root system. Stems of plants weakened by these root-rotting fungi are susceptible to attack by the stem-rotting fungus Fusarium oxysporum. The fungus causes large brown, sunken areas on the main stems near the soil line. If it girdles the stem, the plant will die.
If the plant is only mildly affected, let the soil dry out between waterings. You may need to transplant the plant to a container with a well-drained soil mix. Trim off rotted roots, dipping cutting tools into bleach solution between cuts. Discard severely infected plants and the soil in which they grew. Wash and disinfect the pots before reuse.