PLS HELP!!!!!!!Diesel fem .5weeks from seed.whats wrong with this plant??

Growing medium: cocopeat,perlite,vermiculite
Nutrients:Gh trio series ,rapid start
Ppm:300 ppm (is it enough??)
under MH 400watts.
Ph:6

looks like a PH problem

Yea, PH would be my guess.. Looks kind of yellowish in the pics.

Whats your PPM in the water before you add your nutrients?? Also with Coco (i found out the hard way also) is that you really need to add a Calcium/ Magnesium supplement. Cal/Mag helps with the uptake of Nitrogen (im pretty sure... Someone could correct me)

My first thought is ph as well. Give it a good flush, and get ur ph right after adding nutes. And then at the end of your flush, add however much water with nutes. Bam! Another case solved.