Beneficial yeast in cannabis cultivation is a legitimate scientific idea borrowed correctly from real agricultural microbiology and then extended, without direct evidence, into cannabis-specific marketing claims. The mechanism is credible. The cannabis-specific magnitude is not yet proven. That makes it worth a careful, controlled experiment for the curious home grower, and premature to treat as an established best practice for anyone running a commercial room. Test it in a corner of your grow before you test it on your whole harvest.