This research presents a novel method for paste-based robotic planting. Our method for robotically extruding seeds in a paste of clay and planting media enables precise, algorithmic planting. This additive manufacturing process builds microtopography, while planting seeds. With this 3D printing process designers can engage with the geomorphological and ecological processes that shape landscapes. Microtopography can be designed to direct flows of water, while planting can be designed to foster biodiversity, form ecotones, and control erosion. As a proof of concept, we demonstrate how algorithms can generate precise planting patterns such as pseudorandom gradients. We envision unmanned ground vehicles with seed printing systems planting entire landscapes with algorithmic designs.