Autoflowering cannabis plants will produce denser buds if the light period is continuous since the plant produce all its energy from photosynthesis and therefore more energy means more mass and denser buds. The dark period between the light cycles can increase stretching that will lead to fluffier buds.

The recommended light cycles for autoflowers is 18/6 or 20/4. Additionally, running the lights for 24 hours at a stretch might reduce the lifespan of the light. Even expensive lights made with high-quality materials may succumb if they are forced to grow for long periods of time without rest.

Most growers agree that the optimum amount of light to give autoflowering strains is somewhere between 18-24 hours of light a day. As a grower you should adjust the light depending on the cultivar you're growing. The best light cycle will depend on your growing conditions and growing setup.