You got a jungle of healthy looking plants going on. You still have no mentioned how much height you have to work with max, counting lights and you need to keep the lights as close to the tops as possible. If I were you, I would switch to 12/12 flowering schedule immediately. I would also defoliate the lower branches of many leaves to open it up to light and airflow.
As for your ferts, there are many. I use
Advanced Nutrients PH perfect trio, Grow, Micro, and Bloom. It's actually made with hydro in mind but works great in any medium. The reason, my well water has to be adjusted and this takes all the work out. Just fertilize according to the schedule on the bottles. If you start using powerful LED lighting, then you reduce the feeding schedule 1/2 strength. I have also used the
Foxfarm base trio of ferts, but I find I have bigger yields with Advanced. Many of the growers on here will have their own fertilizer favorites. You can look at my pics, I just harvested today. I have a thread in Introduce Yourself, called Hello Folks. Good luck and feel free to ask away. :cool: