I have not read every comment, but a closet will work if you line it with foil and arrange for ventilation. I am using a mix
FFOF mixed with 1lb of a super soil in the bottom 1/3 of 5gal bags. Ideally I should not have to add amendments unless a deficiency turns up on the leaves, the roots reach for the bottom where the enhanced already rich soil is for the end of plants life. I will add
cal-mag later on and maybe tiger bloom at flowering. I used 2 potting soils both organic, however the
FFOF produced the better of my plants. I have no doubt there are 50 products as good or maybe better than
Fox Farm, but I am not going to waste time trying others when I am satisfied. I just paid $80 for 3 bags from a local garden shop. It is better to shop local, I think.
That is about all I can add. I don't have temp and humidity on bluetooth, don't measure the lights with gauges. I have a temp and humidity gauge hanging from the roof adjust what I can and believe the seeds know everything else. I put seeds in peat trays, add water then put the tray on a heat pad, keep damp and I have had only two seeds fail to pop out of twenty in the past two years. This year I am using dispensary seeds for my tents and in my yard.
As others have mentioned the wonderful odor of these plants can be strong so venting to maintain a correct atmosphere is a must. Where you vent to is also important so you also need a good filter. I just put 6" ventilator on my 4x8 and hope it is enough, it blows hard and the basement is cool anyway so should do. I have a 4x4 with a 4" blower and did the job sell with 5 plants in it but too cramped.
I have heard about flushing but don't understand why, why put something in you want to take out. I don't think stressing the plants in that way is helpful to the end product. I understand some stressing can cause the plants to produce more terps or oils if the atmosphere is dry but flushing seems harmful.
Perhaps someone can fill me in on this and why.