Abstract Sewage sludge (SS) contains substantial amounts of organic matter and essential plant nutrients, making it a potential sustainable fertilizer source. This study evaluated the temporal dynamics of plant-available nutrients released from municipal sewage sludge obtained from the City of Bismarck Wastewater Treatment Plant during a 32-week incubation study. A Zahl-Max-Bowbells loam soil was amended with SS at 10 g kg⁻¹ soil, and nutrient availability was monitored using resin membrane technology. Extracted nutrients were analyzed for nitrate-N, P, K, Ca, Mg, S, Zn, Cu, B, Fe, and Mn. Temporal nutrient dynamics were evaluated using one-way ANOVA. Results showed highly significant temporal effects for most nutrients, indicating strong microbial control of nutrient mineralization and release. Nitrate exhibited continuous accumulation throughout the study, while P, S, Zn, Cu, Fe, and Mn showed early release peaks followed by declines and later stabilization. Potassium, calcium, and magnesium displayed similar patterns with late-season rebounds in availability. Boron remained relatively stable throughout the experiment. Overall, sewage sludge functioned as a slow-release, multi-nutrient fertilizer capable of supplying both macro- and micronutrients over time. However, substantial variation in nutrient release patterns, particularly nitrate accumulation, highlights the need for careful nutrient management to reduce environmental risks and optimize agricultural use.