Example- 9 sq ft of space, 4 plants per sq ft, so 36 plants-
Start with 36 clones (or seedlings) put into 12/12 right away and they just grow one main cola. The space will fill up fast and it's called a sea of green. The advantage is you get buds quicker...if you have a mother plant you have clones already rooted (in 12/12) ready to go into this same space soon as the others are harvested. This way you can keep a perpetual grow and harvest every 6-8 weeks depending on when your clones start and harvest times for different strains.