Question
Hi Wayne,

I have a problem with getting my phalaenopsis orchids to bloom.  I have 11 of them that I have had for over a year and a half. 4 are younger seedlings,  4 are older plants that were blooming when I bought them, and 3 are HUGE older plants that were also blooming when I bought them. None bloomed this past spring, and I can understand that the seedlings aren't mature enough yet, but I can't figure out why the other 7 will not get any flower spikes!  

They are in a bright window (not direct sunlight), are fertilized lightly every other watering, and seem to be healthy and are getting new leaves.

In April I replanted all of them in fresh orchid mix and trimmed the dead roots off. I switched 4 months ago to a "Bloom Boosting" orchid food, but nothing.

Obviously it's something I'm doing or not doing, because all 7 of them won't bloom!

The only thing I can think of is that they are at a pretty constant temperature in the house, (70-76 degrees) with no change of 10 or more degrees. Could this be the cause?

Also I have a friend who suggested I put them in a dark closet for 8-12 hours a day to induce blooming, but I've never heard of doing this for orchids before.

Any suggestions for helping my plants bloom again? I'm going crazy trying to figure these guys out!

Thank you so much!
Cynthia  

Answer
Several thoughts come to mind.  First, use bloom booster starting in December for spring blooming plants and use it for only three months before going back to a balanced formula.  Second, some hybrids will benfit from night temperatures of 60 - 65 degrees which can inititiate flower spike formation.  You might check night temperatures in December at varying distances from the window.  Usually, the closer to the window, the cooler the air.  An east facing window is usually recommended but not required.

Some of these plants are day length sensitive and bloom during the shorter days.  With room lights adding to the day length, this too could inhibit flowering.  You might experiment with the dark closet idea as a way of shortening the day length.  I would just try it for a couple of plants.