Newb to newb answer (no yelling Duggan). My expert friend told me a minimum of 8 weeks. Of the seven plants I have my first indica took that long. The second one is probably another week or two away. The Sativas will be at least that. So ... a) it depends on the type of plant b) depends how disciplined you keep the 12 hour dark schedule. If you screw that up, it slows everything right down. I also imagine it depends on how well your neut schedule works. Do the plants get sick etc.