Imagine a world in which architecture will be 3D printed from living materials. That buildings will germinate, bloom, wither, produce new kinds of materials, and return back to the soil. This article introduces an innovative approach to sustainable architecture, through the utilization of 3D-printed structures crafted from locally sourced soil and plant seeds. After printing, the seeds germinate over time, forming load-bearing designs with interwoven root systems, which exhibit remarkable strength and resilience, reducing reliance on conventional construction materials. The research evaluates the mechanical properties of 3D-printed living structures through a set of material experiments to find a material combination that will allow maximum growth within 3D-printed architectural scale objects. The successful pilot project demonstrated their strength and capacity to support plant growth. The study also addresses the esthetic, cultural, and social dimensions of this novel fabrication technique, offering personalized, native plant-based patterns, and fostering community engagement. In conclusion, this research underscores the transformative potential of 3D-printed root-built structures as a sustainable architectural solution. By harnessing local soil and plant roots, these living constructions offer an eco-friendly alternative to conventional materials, with diverse environmental and social benefits. This study contributes to the evolving knowledge base of eco-conscious building practices, encouraging further exploration and adoption of nature-based solutions in architecture. With ongoing development, root-built buildings hold the promise of revolutionizing design, construction, and habitation, promoting a harmonious coexistence between humans and the natural environment.