If you get serious about lighting you can bring in a crop 60 days from the time the seedling goes into dirt.
That's a routine 4 weeks vegging and 6-7 weeks flowering. With decent lights you can look for an ounce per plant cured.
If you are more concerned about quantity than speed, you can grow bigger plants. Move up to a 5-gallon pot, FIM or trim the top
so you stay under the light OK (makes plants bushier too), and veg for a longer period. Depends on how much space you have
and how much of a hurry you are in. In my 8 x 8 flowering room I have to decide wether I want 12 plants finishing fast in 1.5 gallon
pots or 4-6 mothas producing 2-3 oz/per taking another month to finish. I've been doing this full-time for years and still mostly grow 'em fast and small.
I'd rather experiment with 12 different strains than fill a room, eh?
Good luck, BigSteve.