I wait a bit longer, between 2-3 weeks. I've used lets grow a and b but this time just adding the bone meal. Just added to the tallest. I can't get over how tall and how many bud sites the lowest branch has. Its soon to be talker than me. It's around 4 feet and still growing. I love it. I counted 17 different bud sites for 1 of the lowest branches and normally the King Kong is lucky to get 14 in my past experience with same light conditions only diff is I'm using just miracle grow instead of root farm and feeding.