Hi bud :Sharing One:I start with boost a week into bloom @ around 1/4 strength & increase every week until im @ full strength around week 8 ... thats usually when they get the PK13/14 as well .That gets used anywhere from week 6-10 really ,depending on how fast you want to finish the grow ect .Some strains take longer & would use PK later ,while a quick finisher could get PK as early as week 6 maybe ?.You can run PK13/14 for 2 weeks at a lower dose if you like & these are just rough guides that can be changed to suit every grower / plant :thumbs: