how do I ask this... Does phosphorous help tell the plants "it's time to get going" and kick them into flower mode?
Or is it more like "wait till I see it happening" first?
I believe plants are selective and know what they will need according to the stage they are in and it's a matter of enough availability and not running out rather than excess availability and provided everything is available they will draw according to needs,so imo, no, boosting will not kick them into flowering mode.
Been thinking and reading about this for a while now. IMO and trying to think like an outdoor plant, I believe boosting flower nutes P and K and reducing veg nute N (regardless of nutrient types used) when you see pre-flowers makes sense because you want the plant to think it’s got lots of goodies to eat when reduced light really kicks in flowering mode. That’s why FF nutes schedule shows gradual buildups and reductions of multiple nutes throughout the veg and flower periods. Just wish they had a better feed schedule for outdoor plants that grow for 5 months with flower mode after 12-16 weeks. Guess they can’t please all growers all the time.