A basic setup involves a wooden pole, a copper spiral winding upward, and a grounding spike or buried wire
https://lanedhan819.tearosediner.net/electroculture-gardening-fun-projects-for-teens-and-adults
A basic setup involves a wooden pole, a copper spiral winding upward, and a grounding spike or buried wire, positioned near crops to capture atmospheric ions and gently influence local electrostatic conditions.