Culture Lc Canhamiana v coerulea ‘Cobalt’
 

I have had my Lc. Canhamiana v. coerulea 'Cobalt' since 2010. Lots of new growth and good roots but no blooms. I also noticed that the leaves will easily turn yellow after approx 8mth. I always fertilize weakly, and have tried all the diff fertilizers. I grow under lights, 2 T5s plus 2 6400k full spectrum screw in bulbs. I have moved them in and out of the light and no difference. My friend gave me a division of hers and she has had the exact same problem.
Any help would be appreciated. Thanks! :bowing

Too much nitrogen as well as too much light can impede flowering.

L. purpurata require very strong light to bloom, putting it out for the summer is a good idea.
Unfortunately few orchids are donkey that will never bloom.

To my knowledge the other part is C. mossiae. and flower development of mossiae depends on a variation in daylength. So I would shorten the artificial light in wintertime for 2-3 hours compared to summer, and give it a rest period.

Bingo

This is the trick.

Ahh, I have not given it a rest period, and I did forget to knock back from my 16 hours last winter. I'll try 14. What month do you make the change? Nov? (I'm in Canada)
Thanks to everyone for responding. I truly appreciate your input!

This is very important.
One of the owners of H&R Orchids recommends dropping daylength in winter down to 10 hours. Works for me.

I shorten my daylength by a half hour ever 2 or 3 weeks until I get to 10 hours and started doing this yesterday.

Every few weeks I check the sunrise and sunset times and adjust the lights accordingly, starting as soon as I kinda notice the days getting shorter.

-Ceci

I had LC. Canhamiana "Azur Sky" AM/AOS.
It needs full sun and yes, it probably needs less hours of sun during the winter as it is a seasonal bloomer. Late spring to summer is the flowering season I think.

I'm not sure about the yellowing of leaves, does it happen to older leaves or new ones??
Does the whole leaf turn yellow quickly and then drop??
Does you plant grow normally? This plant should grow quite fast putting out at least two new leads a year. Do you see sheath on the mature growth?

Too much nitrogen causes leaves to get large, week, and deep green, while too little nitrogen can cause leaves to be yellowish and small.

I also have Azure Sky and same problem. It happens on new leaves within a few months. The leaves do not drop off, just sit there looking yellow... :( No sheaths ever.
I use different fertilizers regularly, so not sure what the problem is. I will try reducing lights, but still does explain yellow leaves, just explains why they may not be blooming. It does grow quickly with lots of new leads usually 3 for sure. That's why I'm stumped. Unless the 2 T5's are just too bright? but my friend uses 4 T5s, with no problem....I'm scratching my head...LOL
thanks again