u can switch the light cycle to 12/12 and leave it that way till they show signs of sex,then just flip it back to 18/6..
throw the males out..and once back on 12 hours..if there is any kinda buds on the plants..they will shrink and form funny looking leaves..then go back to normal,it will slow the process down a bit..but if you have the time,and are not in a hurry to bud,then id say go for it..
it would be better on your plant,if you was to just take clones and sex those to find out what kinda plant you have..but cloning isnt as easy as everyone makes it out to be.your call..and ya i grow outside every summer..check the thread out that says...the beautiful earth we live on..i have a few pics of last years crops od's..and if you dont hear from me.send me a mess..sometimes my minds just wondering around.haha..but if i see i got a new mess...ill be sure to reply quick light.and im on everyday in the mornings..i havent much else to do,when im having my morning coffee...oh and i dont have thread of my girls..i should prolly start one uh..heheh...Think i just might now..