Tiny Brown Spots?

Sorry for the unclear pic, but can someone please help me figure out what the hell is wrong.

I realized tiny brown spots on 2 of my leaves...

looks do me that you are over feeding you plants-ghemical burn.
keep up the good work

growing inside,
soil+perlite mixture
15 day old
Given it A TINY bit of Iguana juice grow (once)

It doesn't look old enough to give it nutes yet. What kind of soil is it in and do you ph your water? Your description of just soil and pearlite isn't enough. Which brand of soil and which type from that brand?

Ace Hardware soil
Totally organic.
Contains warm casting, Bat guano and shreds of wood and a few other things (Im a beginner lol)