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

I have Lc. Canhamiana 'Azure Sky' and it has bloomed for me most years, but usually only on one growth even tho it is a robust grower with multiple leads being produced each year. I keep mine under 2 T5's and the leaves do not go yellow and it has almost every single leaf since I got it a few years ago. It got so big, that I split it a year ago and still have at least 15 leads on mine now. It didn't bloom this spring and I assumed it sulked from re-potting. It was terribly tied up in roots and I had to get aggressive with it to split it. But mid summer this year when it had put out a number of new growths, I am seeing one (and only one) with a sheath on it. It seems the wrong time of year for a sheath on this, so I don't know. I have to wonder if this hybrid is just a reluctant bloomer. Mine does get shorter winter days and also much cooler winter days.

thanks silken...so most likely it is not too much light then, so perhaps I'll do some research to see how much magnesium they can handle, and I'll try adding a little epsom salt....thanks again for all the replies!

I do add Epsom salts occasionally but it is very sporadic and pretty infrequent. I also switch between tap water and rain water. If you are using R/O or rain water there is very little or no nutrient in it so that has to be taken into account. I often use MSU but also vary between several other quite common brands for a bloom booster such as Shultz. So maybe I cover my bases by flipping around a lot! It's a very robust grower but I can't say the same of its bloom habits under my care! Good luck with it.

One thing I noticed that seems strange to me, is I think it bloomed better when it was a smaller plant. Maybe someone can explain that for me.

So your friend gave you a division of hers/his. Did the mother plant ever bloom???
To me, it sounds like a mystery, maybe it is a mule?

Too much light may yellow the leaves (unless burn and kill), but the sheaths are usually still made.
Also, the production of the sheaths on this hybrid occurs while the plant is still in growth mode, which extends from late spring to early fall, sometimes even into winter. Then the sheaths will just sit there for many months. The shorter day length for a few months then the return of the longer day length signals the plant it is time to flower.
So I don't think not giving short light hours in the winter has anything to do with flowering in your case since your plant won't even make sheaths during the summer/fall season.

How does the yellowing on the leaves look?
Do the new leaves start out yellowish? or turn yellow slowly over time?
Is it even yellow all throughout or streaks? any brown specks? (signs of iron, mag, other element missing, but again, not likely since you are fertilizing)

---------- Post added at 11:00 AM ---------- Previous post was at 10:55 AM ----------

This hybrid, well, at least the Azur Sky, is very robust grower and great bloomer under HIGH light.
It is very likely that Silken's plant is not getting enough light. Big sized plant of this one should be flowering like crazy. I was in awe when I saw this plant in bloom at a nursery.

I grow all my catts (mostly BLCs and some LCs) right along the large bay window facing south. no curtains. Leaves do turn slightly yellow green on certain plants, but all are doing fine. I'm having the best cattleya year! :)
The only one I had to move away from this strong sun light was the mini cattt (Tropical Pointer) that was getting sun stroked. lol

My friend's plant has never bloomed, before or after she gave me the division. The new growth is always a good green with no marks at all, and many of them. The yellowing starts slowly and after approx. 4/6 + months (never noted how long it takes to yellow the entire leaf) they are yellow but are firm and never drop off. They are just like a good leaf except for the colour. I am going out of town for a few days, but when I get back I will post a photo for all to see. I use tap water and also use MSU and a variety of other fertilizers, and my others plants are doing just fine, except Bc Maikai ‘Louise’ AM/AOS is also showing the same yellowing issue but not as severe and it has not bloomed for me either, I've had it since 2010. Lots of growth though. Azure Sky also seems to have a touch of it too, but not as bad as the other two. I have 110 orchids so I guess it's not bad to just have a few that are problematic. So, I will post the photo by early next week. Thanks for all your help everyone!

Mine could use more light since it doesn't seem burned or too yellow. But it is under 2 T5's all winter and in summer it is still in the greenhouse which is so bright. So mine does not seem light challenged. My Vanda bloomed in that light! However, there are places where I can still give it more so we will see what next year brings.

---------- Post added at 11:41 AM ---------- Previous post was at 11:39 AM ----------

Bc. Maikai does need a LOT of light. I gave mine more this summer and see more sheaths than I did last year.

Good info! I'll give Maikai more light then.
Thanks and good growing!

Ok, with so many plants you grow, this one does sound like a mule. The fact that your friend's never flowered ever back it up too.

you know...I think I have to agree with you...overall I'm doing pretty good. I had a few paphs start to go yellow on me in January/February, just after blooming, so not sure if that is another issue altogether..but I did increase magnesium and they both came back with nice green leaves and have stayed green, so I may have been a little shy of fertilizer at that time as I was very busy...but I do believe I have a mule in that 'can of ham!' :rofl:
Happy growing!
Helen