What happens if we keep fungi hungry or overfed? We discover fascinating dynamics: hunger sends an exploratory network racing outward, while overfeeding yields plenty of growth but ever less architecture. The most elaborate network emerges in between! Rhizomorphs are root-like fungal networks that transport water and nutrients and allow fungi to explore new territory. In new work with Sarah Naeher, we find that the architecture of these networks is strongly and non-monotonically controlled by nutrient availability. Moderate nutrient limitation drives the fastest, most coherent exploratory growth. Intermediate enrichment produces the largest organized network, reaching ~975 mm in total strand length. Yet adding still more nutrients reverses the trend: overall fungal coverage remains high, while the organized rhizomorph network becomes less elaborate. This reveals a resource-dependent architectural strategy: exploration under scarcity, extensive network construction at intermediate resources, and increasingly locally consolidating growth when resources are abundant. The amount of fungal growth and the architecture of that growth can therefore become distinct biological variables. ▶️ Why this matters: Fungi are increasingly being explored as living building blocks for sustainable materials. For instance, mycelium-based materials are lightweight, biodegradable and potentially useful in construction and packaging, but their mechanical properties remain comparatively weak and variable. Rhizomorphs are particularly interesting because they are highly organized, differentiated structures capable of long-range transport and mechanically invasive growth. ▶️ How we did it: We tracked their development over time using imaging, SAM 3 segmentation, skeleton-based network analysis and growth modeling. Interestingly, excluding ambient light produced comparatively little detectable change; nutrient availability was the much stronger control variable in these experiments. The engineering implication is exciting - we can learn to program the environmental conditions and let the organism build the architecture for us. Nutrients, moisture, temperature, confinement and mechanical cues could become design variables, potentially combined with imaging and feedback control to steer living systems toward targeted network structures. Preprint, code and dataset see below.