Help...any tips?

Ok im a complete newb to growing so I bought this lamp and i put some seeds i got in a bag and it has been about 1 and a half weeks since i put the seeds in the soil heres some pictures



my main concern is why one of the plants is a bit yellow? any suggestions?? (PICTURES IN MY GALLERY)

your going to have fun trying to seperate the root systems when you repot do it very soon you might loose the little yellow one good luck

At that young age it is nearly imposible to narrow the problem down to one thing I do however know it is a nutriant def. This is more than likely caused by poor root growth