Cattleyas suffering 2 years after repoting

[jkrobins]

I re-potted two large 10" pots and one smaller 6" pot of C.Jewell Box 'Dark Waters' in May 2013. I Put one large one in S/H and the other in bark. The smaller one which was back bulbs from a re-potting in 2008 I also moved to SH. Nether of the large plants has thrived. They both had 6 or 7 flower spikes with 3 to 5 blooms before re-potting. I have had these plants (or their ancestors) for more than 20 years with many divisions and re-pottings. My idea with the two types of medium was to see which worked best. They both are failing, except for the smaller one in S/H which is blooming and very happy. They are all in the same west window close to a south window which is shaded by an outdoor pergola. My only thought is to divide and clean up the large ones and re-pot them in the same medium they are in now and hope they will recover. They are all in active (if weak) growth. The last time they were divided was in 2008 but they have been re-potted every two years.
The pictures show the wrinkled leaves and two new leads on the one in S/H which are turning black.
Does any one have any ideas?

[Orchid Whisperer]

Based on what I can see, especially the first photo, I suspect that the roots are not drying enough between watering and if you remove the plant from the pot, there may not be many good roots. I am seeing a lot of algae growing on the inside of that pot in the first photo.

For any Cattleya type plant, good drainage at the root is very important. To improve drainage, try switching from plastic pots to something like unglazed terracotta, or wooden baskets, or plastic net pots.

Since the plants have not been re-potted in 2 years, I would re-pot now, switch the pot to one of the better drained options I mentioned. There are several types of medium you can use, but if you like to water a lot, I would try a coarser medium, or something inorganic like lava rock etc. or LECA. The goal is that the medium should be able to dry completely in between watering.

When you repot, you should get rid of any dead roots. You can judge then if you want to divide or not.

I saw some blackened new growths, suggesting you might have a calcium deficiency. You can use gypsum or a commerical CalMag supplement to provide the needed Ca.

Good luck!

[wintergirl]

I like to put side holes in my plastic pots, that helps keep the pots airy.

[jkrobins]

The plants in photos 1-3 and 6 are in S/H pots. Numbers 4 & 5 is a clay azalea pot with drainage slits cut into the sides. I was watering once a week using MSU pure water fertelizer and rain water but I increased the water in the S/H pots to twice a week because I read here that if the reservoir gets too low the lyca can dry out. However, the plant was suffering before that.
Since the small plant is doing well I am wondering if the big ones are just too old and need to have the old parts cut out. Is that possible?

[Orchid Whisperer]

jkrobins, I think you won't have a really good idea of what is going on with the plants until you have a look at the roots. When I see really dehydrated leaves on a Cattleya-type plant, I first suspect that something has happened to kill most or all of the roots. Usually it is too much water.

Take the plants out of the pots, if the roots are fine, you can always put them right back. However, I think you will find that there are a significant number of dead roots.

Whether it is LECA or something else, Cattleya types should dry out before you water again.

Regarding older parts of the plant, if they are green and capable of storing water, there is no need to remove them. If you do want remove the old back bulbs, I would suggest getting the plant into better condition, with actively growing roots, before removing the old sections.