Athosanswered grow question 4 years ago Depends. If it is an auto you need to top removing either the 5th or 6th node, anything later and it will start flowering; keep in mind that once the 5th pair of leaves fully open flowering will start, so the TOPing needs to be done when the node is just appearing. On photoperiods you can top much later, depending on how big you want your plant before flowering.