The flowering stage of marijuana is when your plant begins to produce flowers, which eventually become the buds you harvest. The flowering stage of the cannabis plant occurs after light exposure is reduced. If the marijuana plant is kept in the light for 18 hours a day, it will stay in the vegetative phase forever, and converting the light cycle to 12 hours of light and 12 hours of darkness will begin the flowering phase.
The length of time the cannabis plant is in the flower during the flowering phase depends on the type of cannabis you are growing and the conditions under which you are growing. On average, marijuana plants will bloom for 6-10 weeks. However, it may be longer, depending on the strain and growth conditions of your plant.