How early can you start early sexing

2 Weeks into vegetative you can usually start seeing pre-sexing parts. although you never know for sure until you start 12/12

 

p.s dont you have a podcast radio show?

 

Ha that's funny, well glad another fellow so cal resident has decided to have their own garden! whats your setup right now?

 

you mean take a clone and put it at 12/12 for it will sex?
i think thats the fastest way but i use fem. seeds and ive never done it.

 

A clone in general should already be female unless otherwise specified, so there is no need to sex it, unless you received it from a completely unreliable source.
There's no point in cloning a male, unless of course you're preserving it's pollen for future breeding.

The reason some people force young clones to flower, then revert back to veg, is for the benefit of the intense branching hormone that is released during the onset of bloom.
It's what causes the nodal spacing to shorten and tighten into what we see as the 'bud'. If you use that to your advantage, you can achieve very densely branched plants, with little to no training.

I go one step further and avoid any delay (and pre-bloom stretching), by taking my 2" - 3" cuttings directly from plants that are already well into bloom. The branching/flowering hormone is already present while the plant reverts to veg as it roots, and the first branches to appear come out in large bushy clusters, instead of mere pairs, as seen here:



And to answer the original question, in two to three weeks from seed you can begin telling gender, without any sort of lighting adjustment.

Most plants will show signs of sex once they reach maturity under any light schedule, even 24/0, while a lesser ratio may sometimes require the light schedule or the temps to drop first.