Need Help! Plant has brown spots...

Hey,

Although I have no camera, I can give you a backround on my plant.

Basically, my weed plant is about 2 weeks old, small stem that has 2 starting leafs on it (very round like) and 2 semi-grown ones (they look very rigid). It also has 2 very small leafs forming on the top of the 2 leafs (rigid). The plant is very green and has adequate sunlight 14/10 from a 24w Flourscent light (1000 linens). The issue I am having is these large brown spots forming on the bottom of the 2 first leaves (rounded ones), almost half the leaf is semi-brown. There is also a very light hue of red on the stem, and a very light amounts of yellow ontop of the plants.

I figured that I had overwatered the plant a couple of days ago (very moist water even after night) and feed it a bit too much nutrients. Could this be a result of overfeeding, or bad soil?

Thanks for your advice.