Advice on when to flower

Hey was wondering if you guys can give tips and feedback these are my babies so far 1st pic recovering from root bound don't mind the set up I jus had to move things momentarily I grow inside a Vivosun tent and I also have 1 more light not in picture recently experienced root bound and had yellow leaves so I transport into mg performance organizes in 9 gallons was wondering when I should flower so I don't run into the nitrogen toxicity that you get growing with miracle grow

Flowering the 2 big ones in the back

get them out of the miracle grow

Get them healthy before you start flowering. Leaves look like they’re yellowing. Little guys look really burnt. I would also get away from the miracle grow.

get some magnesium for the little one middle left