Originally Posted by emilya
they will keep vegging until the dark period gets to 12 hours. At 12 hours of night or more, the plants feel winter coming on and they switch to flowering mode in order to reproduce and keep the species alive.
Most indoor growers use either 24 hours of light or at minimum 18 while in vegetative (there is a controversy as to whether the 6 hours of darkness is needed at this stage) and then switch to 12/12 to start the 8 week flowering cycle. So at 16/8 the plants will not go to flower unless they are an auto-flower variety, but many would argue that you are wasting 2-8 hours that you could be using to provide the light which gives the plant the energy it needs to grow.
Also keep in mind that if you put the plants outside in the spring, it is going to be a long time before the nights get back to 12 hours or more to send the plants into flowering mode and start that 8 week cycle. This is why indoor growing is so popular... it gives you much more control.
Emmie