Phalaenopsis flowers failing to open completely

[Ioana]

I grow under lights and on windowsill in winter, outside in summer (in Michigan). Most of my phalaenopsis are quite happy, growing vigorously and spiking/blooming well, but a few plants have flowers that don't open completely (they look like the licastenoid ones, but aren't supposed to be).

First had the problem last year, all in new plants. Thought it might have been too dry, so this year have a humidifier, the room is kept ~ 60% humidity. Didn't help: same plants have the same problem.

No other plants affected (although I do have one other Phal that dropped several buds, also did that last year). No visible bugs on the affected plants.

Temperatures ~ 75F or so during the day, drop to about 65F at night.

Any thoughts?

[Paphluvr]

Temperature and humidity sound good. What is your watering schedule like? Have you ever seen the plants in question bloom normally? It could be genetic.

[Ioana]

I have them in a medium that drains pretty quickly; water twice a week generally, although sometimes I get busy at work, and it falls to once a week.
Summertime, they get watered 2-3 times a week, depending on temperatures.
The 2 that are not opening normally were bought last year:

Phal Diamond King has bloomed twice now, all flowers abnormal.

The other one is currently in bud. It's Phal Harck Pearl, a medium multibranched harlequin. Last year it had some branches with normal flowers, others with some or all failing to open. It was in bark, I repotted into my usual mix after it finished blooming.

Looking forwards to any suggestions..
Thanks!
Ioana

[aliceinwl]

My guess would be some genetic predisposition. It seems like expression of peloric traits like this is variable. I have a Phal that did the same thing on its last two rounds of blooms (mix of normal flowers and flowers that don't open). I've seen a number of these show up in stores too, now that I've been on the look out.

[Ioana]

Makes sense... I wonder if there is a known trigger, or if expression is random?

[Paphluvr]

I believe that by definition harlequin Phalaenopsis orchids are mutants. Perhaps some other resesive gene is causing the problem. You might give it one more blooming. If it does the same thing it's compost heap time. I assume you purchased this not in bloom.

[Ioana]

Correct.. And thank you for the suggestion!
Ioana

[aliceinwl]

Some people like them so if its a healthy plant maybe re-homing would be an option too? I'm giving mine at least one more season to see how things shake out.

[Ioana]

For the Harck Pearl, I'll definitely give it another chance: it was stunning last year, even with some deformed flowers. The other one is not impressive, only 5 flowers on the spike and I'm really short of space, so it'll probably be compost.