I have an eletric fence but I´m in a really wet land.
Here in Brazil, the eletric fence instruction manuals recomend that you bury the grounding rods in a hole of approximately 3 ft. and fill up with charcoal and enough water to cover them. Then cover it with dirt.
It´s supposed to last up to 3 years.
Other recommendations:
- the longer the rod, the better
- you should have other grounding rods every 1300 ft. and also the more, the better
- make "bridges" between the grounding wires along the fence every 30 ft.
Hope it helps.
