no you cant,i had outdoor that had 3 frosts and never purpled,but my jack frost and god bud went black purple,the god bud looked like purple leather leaf.but a lot od the kush mountian strains purple with out low temps,but get even darker when cold at night.but not all strains will purplei know its not less potent, i never said anything about potency, i just wanted to know if u could basically make any strain purple by having low temps.