I have 8' ground rods. If it is placed in a drip line it is more effective as the ground there tends to me more moist. Only around 4 to 6 inches of mine stick above the ground to connect my ground wire. You can have more than one ground rod too. Also the charger has to be powerful enough to hurt the predator so it will get the message. If it isn't a quite strong zap the predator can get used to the tickle and go right through it.