Digger Zombie Strategy
The Digger Zombie uses its pickaxe to dig into the ground and avoid plants. It will dig to the far side of the lawn and it will eat plants from left to right, never attempting to get into the house.
Split Peas will shoot backward and take out Digger Zombies easily. A Magnet-Shroom will take away the pickaxe, taking away the ability of the Digger Zombie to tunnel underground.
Potato Mines are also effective as stopping Digger Zombies, as they will explode as the Zombie is going underneath them.