A lot of literature including that from books and various websites are of the opinion that marijuana is an annual plant to mean that it germinates flowers and dies in one year. All these claims are untrue and the information provided below will tell you why. The life of a cannabis plant is determined by the number of hours of light it receives. If the plant is kept under light for 16 or more hours a day, it will stay in the vegetative cycle indefinitely. Where the light hours are reduced to 12 ...