With Coco and Hydro in general the nominal is 6.0 and with soil I think nominal is 6.5 but I have no idea what it should be if its a mix of soil and coco, not sure what the advantage would be of doing that. Are you feeding it any cal/mag? They dont need much of anything in Veg in a soil grow, my luck with worm castings and bat guano has not been good at all, too much N,