I’ve seen a lot of people say that uninterrupted light during vegetative state is ideal for marijuana plants. In biology class, I was told that plants need both light and dark periods. Energy is produced when it’s light out and the plant uses that energy when it’s dark. Lab experiments have indicated that plants have a reduced growth rate under uninterrupted light.
Plants photosynthesize during the light period, but they also continue performing metabolic functions like respiration and growth. Observations of similar marijuana gardens on 18-hour light cycles and 24-hour light cycles indicate that marijuana itself does not need a dark period. The plants grow about 33% faster with continuous light than an 18/6 light regimen.