Reply To: Flush before Harvest

[Somatek]

The debate around whether to flush or not before harvest was really kicked off by a paper published by the UoG which you can read here.  For normal people who aren’t interested the quick version is the study was looking at optimal irrigation strategies for growing ganga in a controlled enviroment.  The part about flushing was a small blurb where it tests the theory that flushing reduces the mineral content of the finished bud, which it showed was false and had no substance as the mineral content was the same between the test and controlled crops.  That is far from definitive though as their was no blind qualitative testing with a large enough sample to draw relevant data from.  It also didn’t consider the context around flushing which is that it was common advice when growers aimed to slightly over fertilize their crops looking for the “optimal burn” as a sign of proper fertigation instead of using something like a brix meter to dial in the ideal based on solid data.  Remember this was a study looking at optimal irrigation strategies where the test vs crops had every variable controlled and measured from VPD to plant size and biomass yield, etc.  Which is a very different context from growing in the 90’s when flushing was prominent.  Finally they also observed there wasn’t a significant difference between the control and test in terms of yield or potency, which suggests there’s value in flushing simply to reduce your inputs/costs.  There is no clear answer as like most things the science is still being developed.

An interesting side not of that study is that it found that slight water stress at the end of flowering decreased the yield but increased the cannabinoid content and produced a net gain in potency at the cost of yield.  Keep in mind though the level of control they were applying as it’s probably a thin line between boosting vs stunting the plant.