I've just been re-reading the Harry Potter books for the hundredth time, and I'm finishing up The Chamber of Secrets, but I've found something weird.
Everyone who is petrified (and remember that they are petrified for months), just needs mandrake juice to cure them. Conveniently for the Hogwarts staff, Professor Sprout is growing some mandrakes with the 2nd years in old greenhouse 3.
Sure, it helps the narrative to have a long awaited mandrake juice so that they can't just ask Hermione, but it seems like they should have just gone to Diagon Alley and bought some mandrakes/mandrake juice. Otherwise, they could just send the students to St. Mungo's Hospital.
Is there ANY possible in-universe explanation for why they didn't just buy some? I mean, maybe they are rare, but Sprout bought enough babies for a full class, so they can't be that rare.
It seems like just a plot hole, but maybe Rowling mentioned it in some interview?
Note: I recognize there is one very similar question on the site already, but it was 5 years ago and not satisfactorily asked, or answered.