Need help northern lights feminized

Hello this is my first grow and 2 weeks into the grow the lower leaves of my plant have been dying and having brown spot on them. I already cut 2 leaves off and tried to give more nutrients as its a coco coir grow. 2 weeks later i find the plant kinda small and i dont know what the problem is.

The 1st question the coco growers will need answered is, how often you water?
My guess is not enough light and not watering enough for coco.
Good Luck!

PH/ EC problem most probably!

You're going to have to supply a lot more information. The one thing that is obvious is that it didn't have enough light when it started and stretched quite a bit. Did you lower the light?

What are you feeding it? What EC? What pH? How often are you feeding it? What is the light and what height?