mottled leaves on a cattleya

[sevilliana]

I have extreme variations of green coloration on the leaves of some of my cattleyas - see attched photos. any ideas what is wrong?

[Zoi2]

How long have you had them and what kind of culture are you giving them?
Joann

[sevilliana]

I am not sure how long I have had this particular plant - I have this problem on multiple plants - not just cattleyas but on some phales and dendrobiums as well. Some of my plants are over 5 years old - I inherited some of them and they could be as old a ten years but I don't know for sure. All my plants are in bark and they have been fed well water and fertilized - though the fertilizer levels have not been consistent over time.

[sevilliana]

The lighting question is interesting - I am always guessing about light levels in my greenhouse. I have shaded polycarbonite panels and sometimes have hung extra shading cloth but I don't really know for sure how much light my plants are getting. My greenhouse is on the west side of my barn - three exposed sides.

[Becca]

I have the same thing going on with one of my cattleya hybrids....but mine is more blotchy looking. None of my other orchids have this problems so I figure whatever it is isn't or hasn't spread...so I'm just trying to wait and see what happens with future growths. I'd like to hear what others have to say as well about this!

[King_of_orchid_growing:)]

Questions:

1. When you purchased this Cattleya, what shade of green was it?

2. How long have you had it?

3. Did you move the plant from one location to another?

4. If you moved it, are you able to describe both growing locations in detail? Please include information such as temperature, humidity, light, etc.

[sevilliana]

To the King's questions - None of my plants had this mottling 12 to 18 months ago. We haven't been able to control exacthumidity until recently - I'd say we are at 70 - 75%.

My plants have been moved a great deal but always within my greenhouse which is approxiamately 20 x 40 feet

[sevilliana]

The mottling does not look like other sun burns I have had but I have never heard of this concept of bleaching. To the nutrient question - there was an extended period without fertilizer 6- 8 months -however, the plants have been amply fertilized for 6 months since then and there has been no sign of recovery.

[sevilliana]

One thought - last year at this time - we ran out of propane for a couple of days and some of my plants froze to death or were greatly weakened could that have done something.

[nancy]

You might try a dose of magnesium, as a deficiency in this often shows up as a whitish, rather than yellowish, coloration of leaves. And it is not a nutrient that's included in many fertilizers.
A tablespoon of epsom salt/gallon water is the typical dosage. I generally (try to) use ES on my orchids and tropicals each spring, as it not only greens them up but makes the plants somewhat more sun- and heat-tolerant.
It isn't sun damage, I think. And I have roasted pretty much everything, so should know...
Regards - Nancy