Wettas in my soil

do you mean Weta’s the insect? It sounds like a common ground Weta which hide in burrows in the ground. Or they could be young Cicada’s which live in the ground also. They will come up when the weather warms up, fly in to the nearest tree, then fly off. Department of Conservation recommends to carefully remove the Wetas from the area and put them in a new location/habitat which provides them with leaf litter and twigs and vegetation/trees to climb. So do not just dump anywhere. I personally do not subscribe to using any pest control to kill them.