All mix grow

Starting week 2 of Veg, growth rate is super for the last couple of days, going to transplant them soon. Update day 14 The other day I transplanted them into 15L text pots with 13L biobiz light mix, 2L coco from a block with rhizo, 3 handfuls per pot of perlite and a handful and a half of vermiculite. The lamp is at 40-45% at 40 cm and they are on 18/6, they were on 20/4. I turned on the IR for 15 minutes before and after the main lamp from which there should be a slight stretch, we will see if there will be a difference from it. Today I watered 200ml per pot, everything is still organic, I haven't fed. Gelato-k and Mighty grape slightly yellowed their first leaves, I think it's from transplanting, because on the 10th day they weren't like that and it can't be from lack of food, pH is 6.3, my meter is calibrated. The problem should not continue. I forgot to mention that I will also be using Mars hydro's IR and UV light.