Yellow leaves... just wanted to make sure I'm right

I have been experiencing some yellow leaves that curl, turn brown, and eventually die. I think that it is too much nitrogen. It also starts on lower leaves and is sort of making its way up (...goddamnit). I was wondering if anyone could let me know that this sounds right so that I don't have to worry about anything else. The plant food (Fox Farms Big Bloom) I'm using is the first item on this page, it is 0.01-0.3-0.7. Here is a picture of one of the affected leaves.

It's actually too little nitrogen. If there was too much the leaves would be dark green and curling down. Give it a dose of grow big and see if it greens up.