The reuse of excavated earth as a building material is increasingly discussed as a strategy for circular construction. In urban building projects, however, transforming site-specific soil into usable earthen components is not only a material question, but also a matter of production, storage, logistics and coordination. This paper reports on ongoing doctoral research into field- factory production as an intermediate approach between conventional on-site construction and industrial off-site prefabrication, focusing on earthen and timber-earth hybrid components in contemporary multi-storey timber buildings. Based on site visits, expert interviews and project documentation, the paper presents preliminary case-study reports on three European projects: HORTUS in Allschwil (CH), the ERNE AG Holzbau headquarters extension in Stein (CH), and the ALNATURA Campus in Darmstadt (DE). The contribution outlines observed process chains from excavation and material assessment to temporary storage, conditioning, component production, drying and installation. Rather than presenting final findings, the paper structures emerging questions around space, component type, drying time, material variability and actor coordination. It further asks whether strictly project-bound reuse of excavated earth should be complemented by local or regional distribution logics.