Got a new plant - 2 weeks ago and immediately potted in a cedar basket. Growing in a GH - most nights > 57, though colder nights have seen it dip to 55. Day temps get to ~72. Summer will obviously be warmer.
This morning, I noticed the oldest leaf in the 3 bulb division I bought is rapidly discoloring, yellowing from the middle of the leaf outwards.
Am I growing it too cold? Should I bring inside the house (min temps = 66, but going to be house humidity - 40% or something).
Or is this just a plant adjusting to the shock in changing growing conditions and should calm down as it gets used to my space?
I don't want to lose any more leaves. I can try to take pictures and update tomorrow / tonight.
I think it is just adjusting. And old leaves tend to drop anyway, while the pseudobulb continues to maintain the plant. That's not too cold... actually, I have found that I can grow it outside in coastal southern California - it spent last winter outside (night temps mostly low 40's F, but a week or so into the mid 30's) and it has given me two nice umbels (it's a small plant, got it a year ago last summer as a Santa Barbara Orchid Estate $7.50 special) It is growing nicely, none the worse for wear with some low temps and occasional single-digit humidity (like the last couple of weeks, but there have been several episodes like that in the last year) The GH temps should be fine, and humidity will be better than in the house. This hybrid (and its parent Bulb rothschildianum) are among the most cold-tolerant of the genus for the Bulbos that you're likely to grow.
My terrible phone adds purple in a low light setting, so apologies, but you can see the yellow leaf.
Roberta - good deal on your plant!! Mine was like $35!
But its a nice looking plant until the last week or so (the pitting was visible, but the entire leaf was green last weekend).
Your plant is much bigger than mine - my leaves only about 4 inches, 3 p-bulbs with leaves and two without, when I got it I think that it had 2 with leaves... was just a cutting. So it should do fine. For color adjustment... consider a photo editor... I use Irfanview, which is free for individual use. It makes it really easy to make color correction. (Image/Color Corrections) . Powerful software in a very small package.