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

https://thrivegarden.com/pages/the-effect-of-innovation-on-electroculture-gardening-supplies-pricing-availability

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.