bro dont go on what it says on the bottle go with what the plant needs!! pk13/14 imo should be added when the you see swelling just after the first set of pistils have popped and stopped growing.. canna boost is hormone not a feed so i put it in after the first week of 12/12 after the plant has started to show pistols.. the light change triggers the hormone change in the plant so by adding canna boost at double strength weeks 2-3-4 i find i have big rock solid buds at week 7. but hey thats how i do it n it works for me in hydro and soil.. ps the strech on those puppys could be down to the day/night temp diffrence. keeping the day/night temps close stops the strech.