Wait until the nodes are alternating as apposed to coming out in pairs like they do for the first couple sets. then remove the top at the fourth branch after the first alternating nodes. remove all branches lower than the last four at the top and you will end up with a perfectly symetrical plant with four nice colas and a bunch of popcorn. The reason is that if you do it earlier than that you will leave branches that are not as sturdy as the branches that grow in an alternating pattern. (one on one side small space one on the other side, small space one on another side small space one more and top it). count down four and remove eveything lower than that. WAITING LONGER AND YOUR JUST WASTING THE VEG ON TOP OF THE CUT. sorry!!