Depends on the plants. Ive had some that like to go a bit phosphorous deficient through the bulking period mid flower. Purple meristems, leaves yellowing leaving some purple a bit earlier then they should. And ive ended up boosting their phosphorous on following runs.
Most plants in flower ill give fairly even phosphorous and potassium in most growing methods. My land race peaceblaster genetics potassium burn in the leaf fingers pretty easily in hydroponic if the PH gets a little to high, but seems to be a non issue in soil, but im also using a different regiment of combined organic/bottle with them right now.
Usually, im not super picky about my PK ratios unless i have a plant that is. mid to late flower im usually something like 1 part N to 3 parts PK. But some plants do better with a bit more nitrogen, and some of my land race sativa origin lineages, at least in a hydro context, like lots of phosphorous, less potassium, and practically zero nitrogen. But my nearly pure indica biggs can make a solid run through DWC at 1-1-1 and like 1000ppm start to finish with decent results and be happy the entire time. The picky peaceblasters usually cant take more then 650-700ppm in DWC no matter how you fraction the ratios
Some plants, if you drive them into phosphorous deficiency through cold nights, or just not giving it in late flower, will have very different color and terp profiles to the flower without much difference in potency though, and some strains, imho, actually benefit from light phosphorous deficiency in late flower. GDP is one that comes to mind. Early phosphorous deficiency, or cold night encouraged phosphorous difficulties would bring WONDERFUL character out of an old GDP cut back in KC. The two options were like 2 different strains almost.
