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

https://daltonbcvh980.cavandoragh.org/electro-culture-for-seedlings-vigor-from-the-spark

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.