I gues it all comes down to how much a person smokes, but if i was to look at my own habbits im preatty much certain that a 250-400w hps in a 3x3x6 ft space would do the trick.
But be advised that you will need good vetilation for a HiD light since they put out a lot of heat! Hid lights ( HPS and MH) are what i belive is the most yield efficient lights right now. The HPS puts out mostly red/yellow light wich makes it the perferred choice in flowering phase. MH puts out mostly White/blue light wich make this the preferred choice for vegetative state. But you dont need both, any of them can be used for a complete cycle, but if you are to choose one, then pick the HPS!
If you were using HPS from the start your plants would be at the very least 300% bigger after 3 weeks.
An experinced grower will be able to pull anything from 0.8/1.5 grams per watt of light used. However this can vary a lot depending on genetics and grow medium used.
This is why its
VERY important to do your homework when you choose your genetics! There are a lot of greedy breeders out there with half ass unstable genetics. it takes a while to understand it after entering the grow world, but it aint preatty..
Hydro will always yield more than soil (if done right), but soil cannabis (especially organicly grown) will smell and taste better. The quality i would say remain the same.
Investing money in a grow setup doesnt need to be very expensive. most things you can build yourself and there are a lot of DIY videos around that are very helpful. Just remember to try and make it simple. Sometimes people but all kinds of stuff they dont really need and end up with a preatty pricy setup that they hardly even undetstand.
The world of growing is vast and questions never stop. There are a lot of different information around on many different forums so with some google skills and advice from friends you make inside the community and fellow growers on the forum i belive there is plenty of information to be found. What im trying to say is.. Get ready to read if u wanna grow weed
. growing isnt rocket science, but it damn sure can be
. And remember to always keep an open mind for discussion about cannabis(not legal crap i mean her i.e.) this will help you a lot.
Also try getting yourself a book about growing cannabis. They are really nice to have and contain loads of good info. just make sure you get one with the basics cause some books are very advanced.
Ill be happy to try and help you to the best of my knowledge.
That said im not a Professional grower, but i have 5 years of growing experience so at least i know my way around the "basics"
.