I highly doubt iron... as my well water is pure freaking iron lol but how would plants only two weeks old have deficiencies!? Shouldn't the be fine off the happy frog minerals in well water, and cotyledons until around the third node appears??? I could see that being possible in the older one if the smaller ones weren't showing the same problems but beings the young ones have it worse than the older one I was thinking that wouldn't be the case but I've been wrong...