Cloning for sex problem

I have 8 white widow plants going right now and I decided to clone them to determine sex.

Well I took my cuttings and placed them under 16 hours of dark 8 hours of light ( I read this is a quicker method) well I have no idea what im doing wrong but its now day 18 and nothing they will not show male or female. They are however rooting very well.

Any suggestions? should I try 12/12 instead?

Thanks

the plants wont switch over til 12/12, so make the switch but they might not root

Thats the weird thing
Im giving them more darkness only 8 hours of light 16 hours of dark
and they have rooted great!!! just no flower?

its weird
so your saying give them more light??

Anyone else? please help

Plants will not show sex until they aer sexually mature. Are the nodes alternating or opposite?

One of the plants that I took a cutting from is showing a defined female preflower. But the cutting is not.
The plants were sprouted the last week of August.
Not sure what you mean by the nodes?

Should I take new cuttings and try them?

Thanks!!!