I cut the spike all the way down. Then the new spike as the full power of the plant behind it. You can cut a spike leaving a few nodes and it might branch and generate new flower. However the flowers on the new branch will generally be smaller.
Agree with Carrie with the exception being novelty phals.
They generally have short spikes held close to the plant which if allowed to stay on the plant will rebloom as well as putting out new spikes. Keeping spikes on these types of phal does not result in smaller flowers and you get a much nicer show on it's next flowering.
A good example of a novely phal and the spike habit is shown in this thread:
^ thanks for adding that Judi, I had just assumed that they were talking about a big box store Phal, and shouldn't have assumed anything! I have a lot of those types, and species, so I should've known to add that info! (one of those days, I guess)
If you want a re bloom, then cut just above the 4th node from the bottom. This according to 2 different TV orchid specialists. It worked for me on 2 different Phals.
Ok thanks!! Is there a season for phal to bloom?? I live in Montreal and the orchids stays inside... Is there any trick to make them bloom? I give them orchids feed from Schultz once every two weeks in the summer and once a month during winter time. Thanks again!!
This is my experience:
I water about every week to 10 days. I could not get any to bloom until I put them in a new garden room I built and the temp changes 8-10 degrees from day to night. They are in a NW facing window and get evening sun through the trees, not enough light for anything but Phals I believe. I'm growing Oncs and Cats with supplemental lights.
My Phals bloom in the spring to mid summer. My last one dropped its blooms this month, but 2 of my Oncs have just bloomed or are in spike.