1. How many plants can I grow using two 200W/6700k/T5's for Veg, and what area do I need?
2. In the same area, I need to know if one HPS 600W be enough for these as well?
3. Will be growing on coconut fiber which is the most available organic/hydro medium I can find... How often, and how much nutrients should I use to avoid build-up?
4. It's all for me, NO SELLING... So, would a feminized mix be a good idea? Or, just the plain old good NL feminized as well?
First off, I'm on my first grow, but I think I've learned a lot from reading and 33 days of growing so far, so here's my two cents. (don't read as gospel)
You really need to pick a strategy first, before we can answer all your questions accurately.
For example, I'll tell you my deal. I have 6 plants that vegged under 400w MH. That is in a 2x3 foot closet. I am going to upgrade to 650w MH/ HPS soon. I can have this much light in my little closet because I cool the hell out of the lights. Otherwise it would burn up my plants. Also I am using 6 plants because that is the legal limit here in CA for medical users. I could potentially cram 30 plants in the little place and still have things work, just differently. Alternatively, I could have only put 1 plant in there. Gotten a huge plant.
So, you can put as many or as few plants under your light. It all depends on how spread out the lighting fixtures are, how well they are reflected to the plants, how well things are cooled determines somewhat how close the lights can be to the plants. And closeness determines intensity, blah, blah.
Quick answer you could easily veg 6 plants. Maybe more, definitely less.
If you veg with 200w for veg, then YES by all means 600w HPS would be enough to flower them. I'm not totally experienced, but I think having the veg lighting be a little closer to the flower lighting would be best. I don't mean it's a bad idea, just that it seems like you are giving your plants a little tiny backrub (veg) before throwing them to the lions den (600w hps). I suggest trying 400w for veg. Make those girls real bushy before switching to flower. If you can afford the 600w HPS and afford the electricity to run it, you should be able to afford 200w extra for veg.
600w should be good for an area of 6'x6'. You could use it in a smaller space if you cool like I said before. You will probably need to cool no matter what, but the smaller the area the more the cooling necessary.
I don't do soil, so I can't tell you about the nutes.
About the strains. Here's my suggestion. Try one strain on the first grow. That give you a little more control to learn what the hell you are doing. If you get a mix, they will act different, and you will be asking yourself "should that one be so small, and why is that ones leaves doing that....." Plus it would make things a little more complicated with different flowering times and such. Also, they could grow to different height making you set them on risers, or having them get shaded out by others.
My dream is to have a constant harvest (every 2 weeks) of like 5 or 6 different strains. For myself. But for now I am trying 2 kinds (would have done 1 but store didn't have enough).
I hope that helps. Let me know if you want clarification or anything.
Good luck bro, it's serious fun. I can't even imagine how it feels to harvest the stuff.
