People can't just buy seeds and expect decent smoke in 3 months, I spent about 2 years just researching about growing before I started up, atleast you haven't spent 1000s on a grow op, but even beans are expensive and I hate seeing seeds die.
In reality mate, if u spent the time looking on the Internet you'd find the solution, asking folks In here, is just gonna get about 50 different answers as everyone grows a different way, then everyone's gonna start arguing cos they think their right.
unfortunately, your photos should be used as a warning to future growers, they sum up beautifully, yet tragically, the demise of a beautiful cannabis plant.
Im sorry for your loss, but you have to imagine, that dear, sweet, innocent seedling, could have been the next 'one in a million' genetic, and you my friend, have just murdered them!
My honest opinion is maybe growings just not for u, if your gonna just pour anything on your plants without reading the label, atleast their better off dying now, instead of 2 months down the road and you've just wasted 2 month. Let this be a lesson, stop growing for a while, read up on the net, and start again in a year or two.
i don't mean to be horrible, but this is probably the best advice your gonna get here!