When the first set of leaves appeared I fertilized, then every few months, till they were off and running. ......
Not sure what fertilizer I was using then, since I have so many.
May have been Jack's.
Think I may have used some of my liquid Orchid fertilzers too, as I am big on experimenting with this and that.
But I am sure any good liquid fertilizer will work.
I just stay away from Miracle Grow.