Oh this is rich, turtle.

Beamed me back to an 8th grade science project. Prob that Donna Nichols chick who got the table next to mine. I spend 2 wks clay modeling a cross-section of how internal combustion works. She get's blue ribbon for placing two plants and a transistor radio on a table. 'course she had those eyes too but... oh well.. prob more closet pervs among the judges than anybody wanted to know.

Just thinking what an obvious miss tho by all the folk who've ever grown.

My first question would be - as i revisit the sci with only elementary knowledge - is how in practice it is all about the resonance and hertz, right? I mean you can't just pipe some FM in and leave it at that??

The MomEarth article appeared (speedread it) to focus on a fixed frequency range. Imression I always had of the phenom was that the stimulation was induced by frequency variations, or melody.

On the other hand - if the ultrasound freqs are best - how easy it would would be to locate a little Piazo thinger in almost any growspace.

Determine which freq is optimal.
Find somebody with an oscilloscope, to CD say 15 secs of the frequency or however...
then I'd use sound editing software to exponentially-paste-out that freq onto a CD.

I think the acidic foliar spray was probably as much a marketing gimmick than anything else.