Need help with Leaves Yellowing and Browning

[godlydevils]

Hi,

Can you all please refer this link:

Orchid growth, what could have caused those yellow and browning of leaves? - Album on Imgur

and advise me what could have caused those yellowing and browning?

and how to avoid that?

[Roberta]

First, Welcome!

The cause? Force of nature. The plant(s) are in the Catasetum group, and they lose leaves in the fall, go completely dormant. Now they need to "rest" with no water until new growth is well-established in the spring. (They will wake up!) The time for repotting is just as new growth is starting (or before). Then again ignore them until new roots are around 10 cm long, when you can resume watering and fertilizing. Here is a link from Sunset Valley Orchids (Fred Clarke), someone who has worked with this group very extensively. Catasetinae Culture . Also search the Catasetum and Stanhopea Forum on this site, especially look for several excellent videos from member isurus79, for culture information. Particularly look at the latest video from isurus79 that addresses the issue of Catasetinae putting out new growth during the time when they should be going dormant. (There are some plants that don't read the books...)

[godlydevils]

Originally Posted by Roberta

First, Welcome!

Please check current health and advise if the plant can survive, attached images.

[Roberta]

Doesn't look great... my feeling is, where there's green there's hope. That small growth that lost the leaves still looked like it was firm, so could be OK ( I don't see it in these photos). But alas, I think that the odds are not good.

[estación seca]

I will reiterate what Roberta wrote. The Catasetum group of orchids requires different care from almost all other kinds of plants. If you know what you are doing they are very easy to grow and flower a lot. If you water at the wrong time, or don't water enough when they need it, they are easy to kill.

Read the links Roberta wrote. Get an idea of what they need. If you sign up for the Sunset Valley Orchids newsletter you will get E-mails through the year telling you what to do in that season.

[SouthPark]

The bulbs definitely don't look like they're in good shape. Quite dehydrated.

The roots in the original pics looks like they had been rotting. Maybe a combination of too much water on roots for too long a time plus cold temperatures. That is - the mention of cold plus wet roots is not a nice combination.

And cold plus wet roots/media ---- waterlogged media. Not good.

The green bulb at least still shows signs of chances of allowing the plant to grow a new shoot from the side. But the media and growing conditions need to be sorted out - otherwise it will go downhill even more.

What you could do is to take some bits out of this pic here.

I was figuring that if catasetums can grow on top of power poles, then it will grow in scoria. And indeed they do grow very well in scoria in my growing area in the tropics.


To avoid the rotting roots ----- choose a watering method or watering schedule or watering amount that avoids getting the media super wet or water-logged. Orchid roots - including catasetum - can (will) drown if they don't get enough oxygen. And that oxygen can come from maybe the air, and also maybe from water that can keep moving at an adequate rate. Water that doesn't move much or at all can lead to the roots running out of oxygen in the media. They run out of oxygen - then die - which leads to other unwanted results.