On Flushing Plants :
I have a Ph. D. in Plant Molecular Physiology and my thesis was on the molecular genetics of plant senescence, so this is a three part answer. As you noted, what people say ‘this bud tastes chemy’ and the truth are always typically far apart. As for plants, they are mostly water, so a reduction in salts makes for a better tasting smoking experience. This takes place because the plant, when under flush mobilizes stored nutrients as well as transpires (goe…s through water faster) when salt levels are low in the soil (it’s looking for more food).
Second. When a plant is sensing limited food, after periods of excess, it stimulates a molecular cascade which moves nutrients from the leaves to the flowers (for real plants, this would to to the seed for the next generation, but cannabis has been bred different). Leaves yellow and flowers (and by proxy, trichromes) swell as they have the benefit of this nutrient reallocation. One final push to be pollinated as it senses nutrient limitations. The extend to which this benefits or doesn’t, depends on the cultivar (strain).
Third would be you want to slow metabolism from excess to limited to desiccation in a measure fashion. This will result in the plant tissue almost arriving at a stasis point where the cells are almost hibernating, but everything is pushing toward the trichrome. This last comment is speculative, but I feel drying too fast sucks moisture backwards from trichrome into plant. Also cause a crisis situation where plant material dies instead of is ‘preserved’, which is a fine line.