As you may already know, on the bottle it says to use PK 13/14 3weeks prior to harvest on a 8 week flowering cycle. Yet on Canna's grow chart, it says to use it at week 3 of flowering, or just after the pistols have started to form. I've search many forums on this topic and there seems to still be some confusion floating as to when the best time to use this. The most clear general answer I got was that you can use in both start and end of flowering cycle, but at the start you have to be careful with dose due to the plant requiring less PK. I seen complaints of yellowing leaves due to the use of PK at start and then others believed that using PK at end of cycle doesn't make much difference if any. Whats your thoughts on this? Canna's website has been contradicting. Also I am currently using PK at week 3 of flowering and I'm starting to see yellow leaves forming at top of plant, though I'm unsure if this is due to the PK or very high light levels. (PH is fine and dropped original dose of canna a&b when using PK) Some insight and experience with PK would be appreciated.