Don't cut off old canes that have dropped their leaves because they sometimes flower again. (even though they do not look like it.
dendrobium orchids require well-drained soil and, when planted inside prefer an east, west or lightly shaded south window. In a greenhouse, about 30 to 50 percent of full sun. Under lights, four 40 watt incandescent bulbs directly over plants. Plants should be naturally erect, without need of (much) stalking, and of a medium olive-green color. Mature plants need a 15 to 20 F difference between night and day.
Nights of 60 to 65 F; days of 80 to 90 F. Temperatures up to 95 to 100 F are beneficial if humidity and air circulation are increased. Low temperatures (below 50 F) may cause leaf drop.
Keep evenly moist while in active growth. Allow to dry between waterings after growth is mature (indicated by terminal leaf).
Dendrobiums need 50 to 60 percent humidity. In the home, place on trays over moistened pebbles. In greenhouse, use a humidifier if conditions are too dry.
Fertilizer should be provided on a regular basis during the active growing period. The exact fertilizer you use will depend on the mix in which your plant is growing. A good general rule is to apply a balanced (10-10-10, 12-12-12, or similar ratio) fertilizer "weakly, weekly" during the period of active growth. That is, fertilize every week at one quarter to one half of the recommended dilution.