Just fill with water and the plant will take only what it needs to visibly grow & flourish on the exterior surface of the planter.
DESIGNING FOR PLANTS. We wanted to design a piece that was aesthetically beautiful but it also needed to serve a function; it needed to be a good home for plants. For this we needed to produce a complex shape for the surface of the terraplanter to meet the needs of the plants. It needed to:
 Hold seeds on the surface while they sprout.
 Hold water for plant roots to drink.
Provide a shape and texture that would allow plant roots to grip the surface.
We used parametric design to create the shape we envisioned, and created several prototypes to test with seeds and plants. After testing we looked for ways to improve the product and refined the algorithm and design to get to the optimal solution for plants to thrive.