All plants have internal timing systems, known as the circadian clock, that enable them to anticipate and adapt to predictable daily changes in their environment. These endogenous, self-sustaining oscillator generates approximately 24-hour rhythms in a wide range of processes, including leaf movement, stomatal opening, photosynthesis, growth, and the timing of flowering. By coordinating these processes with daily environmental cycles, the circadian clock allows plants to optimise energy use, regulate water loss, and ensure that key developmental transitions occur at the appropriate time. Research in the Green Lab combines molecular, genetic, and physiological approaches to uncover how the circadian system functions across scales, from individual cells to the whole plant.