Cymbidiums with yellow leaves
 

G'Day all, this is my first post on the forum so please be gentle.

I have a small (but precious) collection of mostly cymbidiums with a couple of zygos thrown in, and they have had a very healthy and strongly growing summer (in Oz) and are now starting to spike - you can see a spike on one of the cymbids in the second last picture and one on a zygo in the last.

But you can also see a number of yellow leaves right? I've always understood that the occasional yellow leaf was a normal part of the plants life cycle but right now I have at least one yellow leaf on almost every plant!

So my questions are; is this normal? If not, is it a watering issue or a fungal thing?

Finally, given the flower spikes on some plants, should I stop feeding now or wait until all the spikes are up?

I don't see nothing abnormal.
In my oppinion, Cymbs have the ugliest leaves always full of "defects".:biggrin:

:) Thanks for your help.

You should see mine. Of course it could be I underwater it at times. I don't think you should stop fertilizing as I am told these are very heavy feeders. I use slow release on mine. And they also like allot of water.

Yes, I always feed them. Not full dose but half.
About the yellow leaves, you're in NZ, the summer is ending. Were they getting sun?

In Australia actually but no, about 50% shade all through summer.

Welcome to the Orchid Board! You should be giving us advice.

They look normal. The yellowing is from high light intensity and perhaps high temperatures. I also see some sunburn on the sides of some exposed pseudobulbs. You are growing them at the high end of their light and temperature tolerance, which is the best thing to do for plant health. Some people want them to look greener and prettier, so they grow them in a little less light. But I would not change a thing if I were you.

I bet there is an Australian cymbidium society that has online information about how to fertilize in your conditions. In fact, I'd be surprised if Melbourne doesn't have a local society.

Yes, Australia...sorry.

The leaf drop looks totally normal to me - once the new growth is mature, Cyms tend to drop leaves on the older pseudo-bulbs. The yellow-green of the leaves does indicate that they are at the upper end of their light tolerance, but that means FLOWERS. (Given the choice between more attractive leaves and vigorous blooming, I always choose flowers) Do continue feeding. Some Cym growers recommend switching to a lower-nitrogen formula in the fall to help blooming, but I personally have not seen any significant difference - when the weather cools off, one naturally cuts back a bit on watering and fertilizing just because the plants don't dry out as fast when it is cold. Perhaps the seasonal change in regimen has some effect when everything else is perfect... since I'm just a back yard grower, not that refined. Cyms aren't fussy...

And I'm a balcony grower, not that much different, I think.
With time, and under my conditions, I've noticed the best treatment I can give them is to...ignore them.:biggrin: