6 Plants. Thats a big variable. lol I fill a pretty good sized room with 6 plants. One plant per 1kW HPS. 4+ pound trees. I also have a 2x4 foot (I don't do meters lol) tent that I use for flowering seed runs, test genetics, breeding and such, I commonly run 8 to 12 plants in it using a SoG tech. Those are two extremes and you can do anything in between. Longer veg time = less plants in a given area. So if I was running 6 plants for max yield I want those big trees. If I was running 6 plants just to test the genetics then I don't want to invest as much space per plant so I can do more plants (more picks for the winning lottery number lol). So what are your goals with the 6 plants? If it's just make some personal smoke and have a little variety then perhaps a 4x4 tent with 4 plants flowering and a 2x4 veg tent dedicated to mother plants. Or maybe just a 4x8 tent with 6 plants from beginning to end if you don't wish to keep mothers and prefer to wing it each run with new seeds.