Hey guys,
I'm a fan of letting the plant tap into its own reserves, but it's not that easy with organic growing. I would always try to reduce everything as much as possible towards the end, even though an excess of magnesium makes the ash burn white later on... Friends do it this way for better quality traits. I find that the deficiency the plant experiences towards the end makes the terpenes much more pronounced, but honestly, that's just my opinion and experience, nothing scientifically backed. Happy Grow!