Definition - What does 12/12 Lighting mean?
The 12/12 light cycle means 12 hours of light and 12 hours of dark. The normal light cycle is 18/6 for plants. Using the 12/12 light cycle stresses the plants and has a few desirable effects for the grower. One is that it can force flowering and make the plants sex female. The 12/12 light cycle is done in a grow room.
MaximumYield explains 12/12 Lighting
The 12/12 lighting technique makes the grow period last 7-9 weeks. This method eliminates the vegetation stage of growth. It can help some growers conserve in space and time. Using a 12/12 lighting technique from the start means that plants will start to produce flowers as soon as they start growing. The lighting pattern is similar to that of the end of the growing season and it tricks the plants into thinking they need to start flowering.