Phenological studies permit to construct a calendar for the growth activity of the plants, especially, the period of initiation of new leaf buds, appearance of mature leaves, flower bud initiation, and formation of mature flowers, fruiting and seed maturity. Reproductive biology studies thus have to be a vital feature of all conservation projects. Information of the these aspects in Cannabis sativa is required not only for a comprehensive understanding as the efficiency of the breeding system of a species and its evolutionary success but also for effective optimization of yield conservation and rational genetic improvement.