The article discusses the temporal regulation of vegetative phase change in plants, a process that marks the transition from juvenile to adult phases of shoot development. This transition is controlled by the miR156/SPL module, which regulates the expression of genes involved in organ identity and development. The timing of this transition is influenced by both endogenous factors, such as the accumulation of histone marks and the activity of chromatin remodeling complexes, and environmental factors, including light intensity, temperature, and nutrient conditions. The review also explores the role of the shoot apical meristem (SAM) in regulating the timing of vegetative phase change and the interactions between plant hormones and the miR156/SPL pathway. Additionally, it highlights the evolutionary significance of vegetative phase change, suggesting that it has played a crucial role in plant adaptation to different ecological conditions.The article discusses the temporal regulation of vegetative phase change in plants, a process that marks the transition from juvenile to adult phases of shoot development. This transition is controlled by the miR156/SPL module, which regulates the expression of genes involved in organ identity and development. The timing of this transition is influenced by both endogenous factors, such as the accumulation of histone marks and the activity of chromatin remodeling complexes, and environmental factors, including light intensity, temperature, and nutrient conditions. The review also explores the role of the shoot apical meristem (SAM) in regulating the timing of vegetative phase change and the interactions between plant hormones and the miR156/SPL pathway. Additionally, it highlights the evolutionary significance of vegetative phase change, suggesting that it has played a crucial role in plant adaptation to different ecological conditions.