Most Autos are sensitive at that age. Just my experience..and the
FFOF is pretty loaded from what I've heard.
What I do is fill my pot with my soil mix to the top.. Then I remove a party cups worth of soil from the center of the pot. I back fill center with the seedling mix. ( which is usually just Coco and I add perlite to it) .
I if you use Light warrior put it in there.
By the time the roots bust thru they will be ready for theFF soil..
Again that's just how I do my Autos. In finishing pots.
STR8