how soon after the first set of leafs can i throw a seedling into flowering to check the sex? It has its seedling set of round leafs and then it has its first set of leafs coming out of it.
Depends on what you want. If you'd like to keep the seedling as a mum then I would wait until it had a cloneable branch or two. Cut and root the clones and put THEM on 12/12 for a couple weeks until they show their sex. If you do this with a lot of seedlings, make sure you mark things properly so you don't cull the wrong plants This allows you to keep all the seedlings in vegatative growth stage where they get nice and bushy. If you flower it to find the sex and it's too small to produce the yield you're looking for... you're going to have to re-veg it and that will slow the growth and take more time. So what's your ultimate goal?
more or less just to sex a small seedling... I suppose i will just wait a while until i can cut a clone and check her out. Its starting its 3rd leaf set and its 4 days from sprout...