With folded hands I request you, don’t you become hippies again by growing hair. Keep your head cleansed at least once in a month. That is my request. Neither I can chastise you. I am also old man; you are young men.
From Srila Prabhupada’s lecture on Srimad-Bhagavatam 5.6.3 — Vrndavana, November 25, 1976