Help!! having some issues with one of my plants

about 3 weeks old, leaves started to twist a couple days ago and now they have turned black/brown on some of the edges. I also i noticed something going on with the stem, but this could be normal. i recently added some ferts. slow release (i know i shoud have waited), and i am not sure if this is the cause of not. the last pic is of my soon to be scrog set up, im still on the fence about that and the lst method.

Leave them alone, don't give them anymore nutes, they'll be fine. Also in your 5th pic you have two plants in one container, separate them asap.

You burned him with the nutes...

thanks, i figured tha was it. so i assume ill just water normally and hope for the best