I am friends with a few Korean expatriates, one of whom is basically on exile for being caught with some cannabis, and will be arrested and jailed for a LONG time if he returns. The penalty for possession, so he tells me, is 3 years jail time. No fucking around. Cultivation probably REALLY bad... you need legal advice before even considering this; if I were you, I'd give it up. No sense risking going to jail for a lot longer than in the States if (when, if their privacy protection is not as good as we have it here) you get caught.