Sonic Bloom is a growing technique that combines playing of specific audio frequencies and applying a nutrient[/hormone] solution topically to plants. The frequencies have since been demonstrated in studies  to cause plants to open their stomata.
Sonic Bloom was mentioned among the electroculture "Plant Hacks" in Episode 9.
I've extracted the audio from this video and made it available here. If anyone can is aware of (or can generate) a higher-quality sample, please feel free or get in touch!