A basic setup involves a wooden pole, a copper spiral winding upward, and a grounding spike or buried wire

https://medium.com/@entineqelt/electroculture-gardening-simple-techniques-for-bigger-harvests-3a69ca1046f3

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.