cannabineer
Ursus marijanus
Yes. Those roots need to breathe. If your mix is not free-draining those plants might be essentially drowning. Humus/manure without an aerating agent like perlite is possibly badly hypoxic, especially if the present microorganisms are competing with the roots for what oxygen manages to get through,For the stuff that goes through the pot???
Too many possible problems here to do the differential diagnosis without more data.