When should I let B. Nodosa dry out? And another question

[ColoradoBirddog]

I've got good hopes for my B. Nodosa this year. Lots of new growth, looks to be very happy in my vivarium. Plenty of light and humidity.

So I understand that I need to let it dry out for a couple of weeks, to mature the growths and force blooming. But just when should I do that?

Another question I have is this: is there any chance that the growth from previous years, that did not grow spikes, could produce them now?