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

https://www.scribd.com/document/1027298804/ElectroCulture-Gardening-and-Compost-Enhancing-Nutrient-Cycles-164411

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.