Atmospheric nitrogen (N) deposition has caused widespread soil acidification in European forests, particularly on nutrient-poor sandy soils, reducing soil buffering capacity and tree vitality. In this study, we evaluated whether the addition of silicate rock powders (SRPs) could mitigate soil acidification and nutrient imbalance in old oak forests in the Netherlands. We established a five-year field experiment across ten forest sites on sandy soils, applying two SRPs at 10 tonnes/ha in 0.5 ha plots. We monitored changes in topsoil and oak foliar chemistry from early 2020 to late 2024. Within these five years, SRP-addition partially alleviated soil acidification by increasing topsoil pH and the concentrations of exchangeable calcium (Ca²⁺), magnesium (Mg²⁺), and potassium (K⁺), resulting in a substantial increase in base saturation. These improvements coincided with higher foliar Ca, Mg, and K concentrations, although Ca and K levels remained below critical thresholds. Exchangeable aluminium/calcium (Al/Ca)-ratios decreased slightly in the mineral soil but increased in the fermentation-humus layer, although values remained below established thresholds associated with Al toxicity. Soil plant-available phosphorus (P) concentrations were reduced, though without negative effects on foliar P. Differences between SRPs reflected their mineralogy but were modest over the five-year period. Overall, SRPs significantly improved soil chemical status and tree nutrient balance in acidified oak forests thereby providing a slow-release, low-risk alternative to traditional liming for enhancing soil buffering status and tree vitality under chronic N-deposition.