I am new to the orchidboard. I just purchased 2 blue vandas (Pachara Blue and Rober's Delight Black) from San Francisco Orchid show two weekends ago. I am in need of some help with growing them.
My current problem is that, each day there are a couple roots with new black spots appear at points where the root bends. These spots are dry and shriveled and then soon the entire root is turning yellow and increasingly shriveled. Please see above picture link.
Are these black spots mold? If they are why are they dry and not soft? Is the problem that they are too dry?
Here is my current culture condition:
63-66oF at night; 66-78oF during the day.
Hang by a bright south facing window
humidity is 53%-77%
I water them by immerse in a bucket of water for 15min
1st thing in the morning. Then 3 times at night with 1hr in between (3 times because they looked so dry and more roots start to shriveled).
The roots are white and turn bright green as soon as they are immersed in water. When hung back by the window, it takes only about 1hr for them to dry and turn back to white. (at night)
I change to a new bucket of water every day, and I fertilize every other day.
The plant had 4 new flower buds when I purchased them, and they open within a week. (Never seen buds grow and open so fast.)
Please help! How do I keep them healthy and stop the roots from dying?
1) is the problem too dry?
2) should I put the root in vase I as I seem some people do for vandas to keep the humidity higher during the day?
3) did I over fertilize? Maybe that was why the buds grow and opened so fast?
4) How do I promote new roots?