it's relevant in true hydro where the roots are constantly in a circulating water media. elsewhere it gets super tricky.
other media has the same result in various degrees.
it's only relevant to a particular grow method with that particular media. to get the same results you would need to copy exactly. it changes between growers, changes with choice of media, and can change from plant to plant.
some folk successfully incorporate run off as an informational tool. there's at least one on the board who actively does so now - @Wastei - absolutely fantastic grower, but he has the rest of his stuff dialed as well. he doesn't lean on it.
the growers tracking run off are mostly the exception not the rule. most growers quickly discover it's not worth the time.
read through a few journals and you'll find only a handful of folk who have found it useful.
when i first started hempy i used to monitor it. it destroyed my grows until i learned to ignore it. i was trying to use the information feedback the same as in coco, and it was a disaster.
i grow by a read on the plants. i don't need run off to inform me.
