I'm a newb getting ready to start a grow, so I've never done this, but I've done a lot of reading in the past few months. The method of sexing plants that seems most logical to me is "cloning for sex".
You start plants from seed and let them veg long enuf to take a few clones.
Take clones from each plant. Be sure to mark the parent plants, and the clones so that you know which parent produced which clone.
As soon as the clones are rooted take one clone from each plant and force it to flower. Apparently. you can force flowering at a very early stage if you choose. After a week or two in 12/12 light the clones will flower, and their sex will be very apparent.
At this point you can Cull the males, and continue to veg the female clones until you're ready to flower them. You can also keep a clone or two from each plant in reserve to use as a mother once you decide which female plants you like best.
As I mentioned at the beginning of this post, this is all book learnin' so I'd like to hear from more experienced growers regarding the idea of
cloning for sex. (Not to be confused with clowning for sex which is a very different subject.)
Note to JB: Pics r coming. A family crisis forced me to take more time away from my setup that i'd hoped.