In a 4x4 area you can grow oa few plants if you keep them quite well pruned or lst however I'm guessing you want to grow only one plant is that right? There's some nice leds out there. They are getting cheaper but still expect to pay at least $200. My Blackstars cost $600 back when I bought em.
But they're quiet and they're cool running. So that's my two cents. Everybody has their own way...which they always think is the best way, lol. That's just how it is.
Soil is life. You should read a book titled Teaming with Microbes. If you make a good mix all you need do is water. For the three months it takes from veg to harvest. If you want to read about SUPERSOIL there's a lot of info here on RIU.
Other that that I always watered with tap water. I had decent reservoir water. Well water is good. I never liked RO or distilled. That's just me.