With public support for pot growing, and sales clearly heading upward at a quick pace, it's time to start taking pot stocks seriously. If the cards fall a certain way, Canopy Growth Corp. (NASDAQOTH: TWMJF), Aphria (NASDAQOTH: APHQF), Aurora Cannabis (NASDAQOTH: ACBFF), and MedReleaf (NASDAQOTH: MEDFF) could be the top marijuana stocks to buy in 2018. As you might have noticed, all four of these companies are Canadian medical cannabis producers.