No real secret BC. They're in pot of Promix HP with an addition of 30% worm castings for added calcium and nutes. I like to give them two feedings of 10-52-10 root stimulator shortly after they get their first two leaves and give them a good base. This year I've been adding some Alaska Fish Fert and this other stuff I have that's got seaweed, bat,rabbit and a few other types of poop in it. Seems to work pretty good so far.
The lights are on 24/7 for the first couple of months too. I'm so happy that these have actually made it. I really didn't think they would have pulled through.