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

https://jeffreytdct399.iamarrows.com/electroculture-for-school-science-fairs-simple-experiments-that-shine

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.