When can I tell the difference bet. male/female?

Absolut newb here, so thanks for the help....

When can I tell the difference between males and females? They have been growing for about three weeks and they are staring to node and grow like crazy. I'm going home for break in a couple days and they are going to be chilling in the basement. I just wanted to make sure that I wasn't going to miss shit. I'll be back in about two weeks and wanted to make sure that nothing bad was going to happen. They are on 18/6 right now. Thanks!!!

you should be able to tell in a week or 2...you should see preflowers....pictures will help us determine the sex,,post a picture or 2,,close up shot will do...

trust me man, you will be able to tell....


you wont confused those big ass balls....

Here ya go...
https://www.rollitup.org/view.php?pg=faq&cmd=category&id=53