Seedling leaves turning white

[hoary]

I deflask Cattleya porphyroglossa 'Mor' last January and they were doing well. Then the leaves started turning white. first on the smaller plants then on the larger ones. Any thoughts?

[Ron]

Hi

Seedling leaves turning white

.
From what I can see in the photo, a few appear to be dead. I personally "Hate" spag as it one of the biggest killers of deflasked seedling I have used as a medium.
for my Cattlea's I just use a small size composted orchid bark. usually about 5 mm (1/4 inch.) Others use spag sussesfully but my climate gets too cold in winter and they all rot off then.
I am a strong beliver in community pots for just deflasksed Catts etc.
That way you can often controll the water better than 1 small plant in a bigish pot.
sorry but I hope you can save them.
Cheerio
Ron

[digitalgate]

I alway lost seedling when they turn white. All of them.
Did you just add any fungicides ?

[hoary]

I didn't add fungicides, but I was wondering if I over fertilized and the white is burn.