strange browning pattern on lower leaves *pictures

Got a youngling I think going on 3 weeks. with previous plants I have seen the first set of single blade leaves ( after the embryonic leaves ) yellow and wither off over time. I have attached a couple of pictures of the strange discoloration on these leaves . It is growing under a couple of CFL's, I just wanted to see if anyone recognized this as some sort of problem. The taller leaves don't show this, the only hint of this on the upper leaf is shown in picture 2, so I don't think it is heat stress. Any help would be appreciated.

It may just be your lighting but your leaves look rather dark which can be a sign of overnute (nitrogen) which can also cause the other symptoms you are describing. Unfortunately I don't grow in soil but many here do and would probably like to know what kind of soil you are using. :) All info helps....

I'm using a potting soil for now, sphagnum and peat mixture, but I have read that the little yellow balls in the soil can a lot of times cause over nuting. and there are these yellow balls in the soil.

Well as I said I am not a soil grower but here is a link you can try and see if it gives you any insight or tips.

International Cannagraphic Magazine Forums - The Complete guide to Sick Plants,pH, and Pest troubles!

Good luck!! :)