Question
When my moss orchids finish bloom in may or june I repot them in a larger pot and move them to a moist bright lit bathroom.

In a month or so they put out a new spike which blooms nicely.

The flowers do not last as long as the winter blooms ( 3-4 weeks) and after they fall off the leaves all turn yellow and die in 2-3 weeks.  I have been cutting the stalk back to 3 inches but notice the stalk is bright green (healthy).  Am I wrong in cutting it back?  Would new leaves eventually come back on the stalk??  the rest of the plant remains perfect.

Answer
John, I presume you call them moss orchids because you grow them in moss (or maybe you meant "moth" orchids).  I will presume that you are actually growing phalaenopsis (otherwise called moth orchids).  With phalaenopsis orchids, the flower spike actually originates from the base of the leaves.  It sounds like your leaves are healthy and your concern is about the old flower spike.  If the latter stays green, you can remove the portion of the stalk just above the second or third node (ie joint) in the flower spike.  This may result in a branch in the flower spike which can also flower.  Another thing that can happen at a node is that a new plant (called a keiki) can grow and develop roots and leaves. If this is what you had on which the leaves turned yellow and the spike is still green, you may yet develop another keiki at that node or another,

To keep the plant in the peak of health, it is generally recommended that you repot after each flowering.  This repotting in orchid potting mix not only improves the growing environment at the root zone but also allows for the examination of the roots.  Any mushy roots are dead and should be removed.  Healthy roots are firm.