Borrowed this info from C and H.
When the new growth begins in the spring, these dendrobiums like to have an increase in water and fertilizer. Culture during spring and summer is similar to phalaenopsis, with reduced light, increased water, and fertilizer every two weeks (1 teaspoon per gallon of water soluble fertilizer). In the fall, cultural needs change drastically. Bright light, cooler temperatures, and no fertilizer will help to initiate flower buds. Water normally so that the bulbs do not shrivel. Buds will appear when the night temperatures are cooler and the growths have fully matured. This is usually in mid-winter, with blooms opening in January and February.
When these plants are grown in the home, we recommend that they be placed outside in the fall to benefit from the cooler temperatures at night and brought inside just before the onset of freezing weather. They then need to be put into a relatively cool location (such as an unheated room or an enclosed porch) until buds start to form.
Do not overpot the plants. They like to be root-bound and do well in relatively small pots. Clay pots suit them well, as does regular seedling bark mixture or osmunda. Some growers also use long-fibered sphagnum moss for these dendrobiums.
Keikis or off-shoots may form on the stems, and these may be potted as new plants when they start to form roots. If plants produce all keikis and no blooms, too much fertilizer and temperatures too warm at night are usually to blame.