What things do you do specifically, besides the proper lighting, nutrients, the basics, to promote vigorous root growth?
I concentrate on root and foliage production only. If you can grow really great tomatoes and are smart enough to apply those principles to cannabis, you'll do great.
You can manipulate hormonal responses, photoperiods, somewhat without effecting plant vigor, health, and production in a negative way but understand that growing a plant as close to what it's exposed to in its natural environment works best. That means putting it through a vegetative stage so that the phytochrome levels which drives the flowering response has a chance to do its thing. If your cabinet and garden set up is restrictive, then don't grow. Plants are dynamic, they like room to grow one reason why all reflective planes were adjustable with my indoor gardens. As the garden's footprint expanded, I moved the reflective walls outward. This kept the plants bathed in the best reflective light possible.
Soul from the Bros Grimm and I used to battle it out over the vegetative period, what's long enough to produce good yields and potency. He preached that a plant could not reach it's full potential unless there was at least a chronological vegetative age of say..... at least 8 weeks if I remember correctly. He also advised his students that you shouldn't flip to 12/12 until see pre-flowers which he felt was a chronological indicator of plant maturity. He felt that potency was compromised by vegging for a very short period of time. Contrary to what they (Bros. Grimm) practiced and preached, I ALWAYS went to 12/12 within 4 weeks, usually just past 3 weeks from the time a seedling popped the soil's surface. Why? I had no choice, my plants grew/grow too damn fast even with a 7' tall ceiling regarding the light hood restrictions.
There's a balance that must be understood regarding this growing thingie, compromises. Everyone has to learn a program that works best for them, their plants, and stick to it until you master what you're doing.
UB