This is not how you attribute.
PS I've been in hydro since I made my own homemade NFT rails in 1996. Flushes are not and never were necessary because of the semi-permeable membrane that the nutrients cross on uptake only works in one direction, ie once the plant absorbs the nutrients you can't remove them. However flushing will remove nutrients in your substrate if you've over fed. I'm a bit lazy so everytime I need to change my reservoir I'll run 1 day of tap water (250 PPM). I should dial in my nutrients better but I'm lazy and that works. I never flush at the end. Why would I artificially reduce my harvest by starving my plants during the time they should be finishing their bulking up?
See this is where it gets interesting for me.
As you say you can’t remove the nutrients that are present in the buds. Only the growing media.
So the last 1-2 weeks of the plants life it’s packing on it’s last bit of weight before chopping, caylexs have mostly swollen, pistils receded and a plump look.
It doesn’t need many nutrients now. So you flush and strip the media of nutrients so the plant cannibalises itself to finish off. Ideally before any of the actual bud becomes yellow. If you keep starving it (I’ve done it) the centre of the bud actually starts to turn yellow!
So basically what I’m saying is a plant needs x amount of food to ripen properly. It doesn’t matter if it comes from the roots or shoots. The buds have the nutrients right there. Weed is an annual, she gonna die and she knows it! But here’s the cool part.
When a plant cannibalises itself it takes exactly the right amount of food needed to do the job.
Ideally you want a healthy green plant before you taper down or cut off nutrients for a week or so. I think personally 2 weeks is too long. It varies between media.
It seemed pointless to me when I was harvesting last to take all these green leaves off. Good for the compost tho!
I think there’s a grey area to flushing. And many people have different ideas of what flushing actually is!!! Just adds more confusion.
Is it 2x the volume of the pot every 3 days? XD
Only if you have a severe toxicity and you only need to do that once!
For me it saves money, effort and doesn’t make my smoke smoother or harsher giving water for the last 7-10 days. I grow in ‘soil’ tho