Where can you advertise marijuana in California? Marketing legal recreational and medical marijuana products in California has its challenges. Read tips for marketing marijuana in California in this simple guide covering PPC, social media and legal advertising strategies. Let's start with the legal guidelines impacting just about every type of ad strategy: Radio, cable, print, and digital ads can only be displayed where at least 71.6% of the audience is expected to be over the age of 21 - determined by