Question
A white phalaenopsis which has bloomed with a large cane and many flowers for 4 years has'nt even grown a cane shoot this year.It has not been repotted, and the care is identical to every other year.It is, however,putting out many new roots, which eventually dry out as new ones form. Is there something
to be done?

Answer
Pamela, it is likely that your plant needs to be repotted.  This should be done each year after flowering.  Use a potting mix specifically prpared for orchids. Once you have a bag of this special potting mix, soak a portion of it while unpotting your plant.  Rinse all of the old potting mix from the roots.  roots who outer covering has collapsed should be removed prior to repotting.  Only firm roots which turn green when wet are healthy and will form the bnasis for new growth.  Repot into a plastic pot with lots of drainage holes in the bottom. Try to get the aborted aerial roots into the potting mix even if it means removing a leaf that is growing below the root(s). Then place the repotted plant in an area where excess water can drain out of the pot.  Do not water further for at least two weeks, then water weekly.

If you have to remove many roots, you can be pretty sure that the plant does not have sufficient root mass to flower.  With recovery of the root mass, the plant will live on to flower again