when to switch to twelves

Guys I've got blueberry crossed with bubblegum grown from seed (g13 from attitude), they're growing in a bubble system under a 400wcfl. They're about 12" now and looking good,when should I put in for flowering under twelve hours and do I add any other nutes other than what I'm using at minute(cana Flores a & b) at 0.4 on my meter(I've been told to use 1/4 level)

You can switch to 12/12 anytime you want, just depends on how tall you want it to be. I'm not familiar with those nutes, a good bloom nute is what you need.

when ever you feel like it lol