Well first off, good luck.

It is possible to grow a decent plant around 12" tall using 12/12 from start to finish.
I did it with white widow and yielded an ounce.

You will want to make sure you can get your plant right up to the lights as I also have had a plant in 12/12 from seed that wound up over 2' tall. I did not have the lighting close enough and it stretched.

If you veg first, how will you know if they are female? My guess is that by the time you get pre-flowers you will have used up your 12".

I would go with 12/12 right off the bat and LST. if you are lucky and get preflowers early enough you may be able to wrap 2 girls in that space but that would be pushing it. also be wary of heat issues in a small space, evan with floros.
midlifecrisis Reviewed by midlifecrisis on . 12x12" micro grow. Hi everyone, OK in this grow there was a strict criteria to follow, factors included minimal use of electricity/ability to control odors/being discreet and having the ability to be mobile. Eventually it was decided that a foot square box would be built from plywood. It will use 57 watts of CFL (2x11watt 1x15watt 1x20watt) and all the materials used were recycled. The initial plan was to grow the plant onto a screen (scrog) but due to several issues the method is still undecided, this is the Rating: 5