Blue Dreamin' in the South

Started a light feeding at 1/2 strength. I've noticed that the seeds that I ended up popping 5 days later for 2 plants (Ariana & Calista) have caught up with the plant that was germinated in a rooting cube (Demi)... those 2 plants were put directly into my soil mixture just as my largest had been done. I'm doing to stick with this method for germination/seedlings from here out as it seems to work better with my environment and will be cheaper w/o purchasing extra cubes. Demi also seems to have slight yellowing on the tip of the first 2 "true leaves" whereas none that were directly put into soil have this issue. All have been given the same light, water, nutes on the same exact dates/times.