How can we re-fertilize the urban landscape of New York City? This intervention seeks to explore and propose an answer to that question. Through simple and inexpensive methods of assembly and disassembly, the project - imagined and realized at two distinct scales - offers a hands-on experience that makes composting both accessible and educational for the public. By inviting visitors to observe and participate in the composting process - an intricate ecosystem of human and more-than-human actors - the scheme becomes a living learning environment. It reveals the often-hidden labor behind organic transformation, much of which has emerged in response to NYC’s new composting laws. "A Metabolic Machine" then draws attention to the soil and natural systems beneath our feet, working between (and with) past and present to reframe composting as a visible, collective, and emancipatory urban act.