Effects

• Overwatering the zz plant will cause the leaves to turn yellow. The plant stores water in its tuber; overwatering it is akin to drowning it.
  
  

Prevention/Solution

• Zz plants require little water; they can go long periods with out it, even dropping its leaves to conserve moisture content. As long as the tuber remains healthy, the plant will regrow the foliage. If you allow the soil to dry completely before watering, the leaves should remain green.
  
  

Considerations

• Zz plants do well in a cactus-type potting mix because it drains quickly. Standard potting soil has a tendency to retain moisture, which can cause the tuber to rot.