Use the regular walnuts for the zombies that have not reached the red line.
Try not to use them unless a mob crosses the line or there are not enough nuts or room to kill a difficult zombie. Zombies are invading your home, and the only defense is your arsenal of plants! Armed with an alien nursery-worth of zombie-zapping plants like peashooters and cherry bombs, you'll need to think fast and plant faster to stop dozens of types of zombies dead in their tracks. Use one nut for regular zombies, three for bucket wearing zombies, and two for the others.
