I personally use the 18/6 method. I hear the 24 hour a day light tends to be better for clones, if my memory serves me. And as for the size, where did you get the seeds?
Darkness does affect the plant tremendously.
Learning that cannabis is photosensitive is one of the first lessons any grower will learn. Keeping a plant under light for a minimum of 18 hours per day will force it to remain in vegetative state; it will only grow stems and leaves. Keeping the light on 24 hours per day is the most productive schedule. Some once thought a down period is best, but studies show the opposite. This period of growth mimcs early spring and the plant responds by growing the foundation necessary for a heavy flowering.
When it comes to forcing the plant to flower, the light schedule must be changed to a 12 hours on, 12 hours off regimen. It was once thought that slowly shifting the schedule to 12/12 was the best idea. One day of 16/8, 14/10, then finally 12/12. I guess the thought here was that suddenly changing to 12/12 can be a bit of a shock and slowly adjusting the schedule is easier on the plant.
Newer knowledge and practices suggest something quite different. One must first understand how cannabis’s hormonal system works before they can understand why a prolonged dark period between veg and flower will jump start the process. When the plant encounters darkness it releases hormones to signal that the flowering period is beginning. It takes a few consecutive nights of darkness before the plant realizes the pattern and the process actually begins.
By turning off the light for up to 36 hours after veg and right before you start your 12/12, you assure the plant hormonally that flowering is occurring and it will release more than enough “triggers” to start flowering a day or two early. While some think that this shocks this plant, its totally the opposite. The only thing that occurs differently is that you’ll see flowers appearing earlier than if you did it the traditional way. Save a few days at the beginning and you can start your next cycle that much sooner. Who wouldn’t want that?
