DON’T DO IT!
Invisible Adjunct explains why professors should try to talk their undergraduates out of going on to grad school. She makes some good points.
Back in my professorial days, I used to do exactly that. I also tried to disuade those wanting to go to law school, for similar reasons. It’s not that I think academe or the law are not worthwhile endeavors; both are. But, as IA notes, most students go into grad school with very little understanding of what they are in for and an unreasonably optimistic view of their future employability. Likewise, I think the vast majority of law school wannabes are drawn by the lure of big salaries and a totally inaccurate image of what lawyering entails.