Imagine a world in which the buildings around us can be 3D printed from living materials. A world in which buildings will germinate, bloom, wither, produce new kinds of material, and finally return to the same soil from which they emerged. To Grow a Building is a performative lab space that uses 3D-printing technology in real time to create live structures. The project constitutes a portal into a future world where some people will build buildings, and others will grow them. To Grow a Building presents a robotic arm that constructs a building designed by a digital workflow. It is a custom-made machine that can execute a complex task: 3D printing of a structure composed of seeds and soil. The design is coded and linked to the robot’s computer. The robo executes the command for the digitally designed structure by taking a mixture of soil and seeds used as building materials and printing layers of the mixture one on top of the other. Upon completion of the printing task, the structure receives a life of its own: the seeds sprout, the walls are adorned with a green facade, while on the inside they fill with dry roots – a new and strong material in itself. Instead of buildings made of concrete and steel, the project suggests an architecture that uses local soil and roots as structural elements. As the world faces an ecological crisis, the use of industrail and non-local is only increasing. To Grow a Building presents a new approach of integrating flora into the design process, by developing a novel material for 3D printing, through which seeding is an inseparable part of the fabrication process.