The Ariana planter waters when your not looking and helps keep your plants from drying out. Here's how: Inside the planter, at the bottom, is a hidden reservoir that holds approximately. 1 in. - 3.5 in. water (depending on planter size). This self-watering insert keeps dirt and roots above the hidden reservoir line while constantly providing healthy greenhouse-like moisture through the evaporation process. If your just not home very often, self-watering containers are a must-have.