You guys are awesome, thanks for all the help. I'v done some reading and would like some more opinions if i can proceed.
So I'd use 5x 3 gallon pots, with the bellow 3 lights with HPS 600w light bulbs. Should they be enough and do the job?
I think with the light bulbs the temperature should stay around 20°C as i mean to leave the lights on during the night and than turn them down during the day. I'm going to do the 18/6 cycle followed by 12/12. If i understand correctly it takes 3 weeks for the plant to start flowering? Does that mean that you maintain the 12/12 cycle for the remainder of the plants life?
Is it enough if i open a window once a day for the air to change?
Also can i successfully grow the plant without adding nutrition? To be honest the whole nutrition's and Ph levels confuse me, can i just water it or is it best to also add nutrition's? Also how much should i water the plants?
If you’re growing indoors, you’re presumably doing it for the benefit of having total control of the grow. For example, the box I built has a 600cfm exhaust fan at the top and intake vents at the bottom with filtered intakes (this is important because you want clean air entering your grow space). So, anytime the fan is on, the air inside is exchanged with fresh air from outside. But this is different than leaving a window open for air. By doing this you expose your crop to environmental factors such as mold, mildew, and pests.
Regarding your lights, I’m not sure If I would recommend them or not. Are they powered, or do you have a ballast to use? Why not go with a proven grow light and build a legit DIY setup and get out of this what you put in. You’d be amazed how well it grows when your environmental factors are in control.
And to answer your question about when they flower. My autos started showing signs at 3 weeks. I’m currently on day 34 growing 4 strains, and 3 of the 4 are fully forming buds (couple pics attached) and the final one is just beginning to push pistils, so it depends upon strain.
regarding light schedule- leave it 18/6, or 20/4 the whole way for autos. If you start with 18/6 I’d stick with that.
I would suggest that you start doing a lot of research and answer the following questions before you begin growing:
1) where will you grow it?
2) how will you precisely control humidity, and temperature? How will you prevent extreme temp swings in either direction?
3) what medium are you growing in? (Soil, hydro, coco)
4) what nutes are you going to use?
5) have you sourced your water yet?
6) do you have a pH meter? And do you know the pH of the water you’re using?
Those factors are so critical to growing some quality herb. Sure, you can grow some crappy basement weed In sub-optimal conditions, but why would you want to?
also, I stress, do some research and learn about the link between nutrient absorption and pH. A big part of the plants production depends on that factor and it’s not that difficult. Google is a wonderful thing!