First of all Iam a newbie and learning.Trying to sex a few plants that are about 3-4 weeks old.How many nodes do they need in order to sex them? I had them on 24 hrs since I potted them and just changed them to 12 and 12 this morning.I just have them under 1 4 ft fluorescent light (2 grow lights)with two extra daylight single bulbs to help. I was hoping to sex them before I changed light cycle but didnt know what to look for.I read somewhat but hard to spot and pick out which is which.What should i be looking for?thanks