I just started fertilizing with Grow More 20-20-20 (not urea free). 1/4 dose, twice a month. I didn't fertilize in the winter but now that I am seeing new root growth in some of my neos, I started fertilizing very lightly.
Quite honestly, I don't know if they're picky with fertilizer. They started growing new roots without the help of it and I only started dosing AFTER seeing root growth. I did a bunch of browsing through the forums about fertilizer and the general consensus was to just use whatever you can get for orchids. Any is better than none. And since I already bought the 20-20-20 before doing any research about using urea free products, I'm just gonna stick with it till it runs out. (Gonna be a while...)
I fertilize the day after I water my neos (and other orchids for that matter).
I can't really tell if it helps or not. Root growth is root growth to me