Question about Nutrients and Gender - please help!

Hello - this is an update of another message I started, but has since gone down the tubes. I have a question about nutrients and when and how to start using them. These are plants I started outside - without proper sunlight I moved them inside to get them growing. They've been inside for over a week now. They are in Miracle Gro soil, which I've been watering to try to wash out the prepackaged nutrients. Also, if you can tell by the pictures, about how much longer should it be until I know the gender of these plants? If there is anything else you see, please comment - I'll take any advice I can get!!! Thanks!!! Pictures below -->

Link to other blog

with mg soil, you'll not have to fert for at least 60 days... NO NUTES!!!

you won't be able to tell gender until the plant reaches sexual maturity (4-8 weeks). or you can throw them into flower and wait and watch...

love, brooke

Is there something in the plant in particular I should be looking for to help me understand what stage my plant is in? Can I measure some part of the plant to help me know better? Also, what is the general yield of one plant? Thanks!