Missouri Medical Marijuana Dispensaries in 2020 are not likely to open up for marijuana sales at the first of the year. But there will be so much excitement that the time will fly by. Before you know it, the first Dispensaries in the newly legal state gets the first batch of lab-approved, cured Marijuana. As patients flock to theses lucky dispensaries, the marijuana cardholders usually have a month to sample dispensaries. After a month, the patient should choose the collective or dispensary in which they would like to belong.