If it's still in the growin phase u can jus switch over, but don't do any less than 14 hours of light. If its flowering everday add on .5 hours of darkness. i.e. Day 1: 24 hours on, Day 2: 23.5 hours on and .5 off, Day 3: 23 hours on and 1 hour off just keep doing that until u get to 12 hours on and 12 hours off. In the flowerin stage the dark peiods cannot be intterupted by any light! AT ALL!!! If u hav to use some light don't allow more than a very pale moon of light and only for less than 5 minutes. Like I said before to keep the plant short and wide take a paper twist tie and put round the top of the plant and bend it to a 90 or 180 degrees angle and tie it to the bottom of da plant. leave it for about a week then untie and it should keep plant low and bushy.