Ariana collection by Bloem: 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 you're forgetful, or you're just not home very often, self-watering containers are a must-have. There also helpful if you're growing in an area that's not convenient to a water spigot, such as a balcony. How a Self-Watering Planter Works: Inside Bloem's self-watering planter, the potting mix is held above the water line by a sturdy screen. The water chamber is connected by small porous channel filled with soil, which then acts as a wick. As water is used by the plant or evaporates from the surface of the soil, capillary action draws more water up from below. The soil has just the right amount of water all the time, but also maintains air pockets, which the plant roots need to stay healthy.