Leaves with yellow spots please help!!

I have 13 babies all 26 days old and some of them have yellow spots on a couple leaves. One has brown on one leaf. Can someone please tell me what they are from and if I need to worry. this is my first time and I would like for it to be a success. Any help would be gretly appretiated. Thanx in advance.

Read the FAQ!!!! It even has pictures!!! That yellow leaves question pops up multiple times each fucking day! Read the faq and answer your own question!!!