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

https://blogfreely.net/galenacmeo/kids-in-the-garden-fun-electroculture-projects-for-families

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.