A friends father who holds a degree in agronomy and works as a plant specialist for a nursery chain said these things really do work well, but you really need lots of experience growing and shouldn't think about buying one unless you have a way to maximize all variables from nutrients, lights, CO2, etc.
According to him, unless all other variables are maximized, it will have little noticeable effect. To which I countered that if I already had to maximize everything else, how did I know it was not my other adjustments as opposed to the harmonizer causing the better yield? He said - "because the kind of pumpkins you'd be growing will be fit for a freak show, and will not be expected. You will notice the difference."
He said he had seen pictures of strawberries and tomatoes grown that way - sweet 100 plants that were so covered in tomatoes you could barely see any foliage, and strawberries that were fist sized. I have seen some fairly large strawberries in normal supermarkets on occasion, so I don't doubt that it might be possible to push even more. Plants do not have a determinate growth really.
A lower frequency is said to have existed back when larger creatures inhabited the earth, and in one emergent school of thought, is the cause of the gigantism seen in prehistoric times. Check it out!!! www(dot)origin-life.gr.jp/3701/3701007/3701007(dot)pdf
I really really really really want to see what this does to cannabis by a truly experienced grower. I am way too much of a nube to invest. Please let us know your results!!!!!