Quarries and minesites are examples of extreme disturbance. Frequently, materials that form soil are scarce and ecological restoration is easier to achieve than productive land. Establishment of soil microbial function is critical to ecological restoration and a key objective of the study. An organic fertilizer containing a mix of sewage and paper sludges was designed to promote soil functioning during the revegetation of slate waste. We compared soil formation under naturally established birch trees (Betula pubescens) on slate waste with that of container-grown seedling birches of local provenance in slate waste amended with either organic or mineral fertilizer. Hypotheses that an organic nutrient source would lead to more rapid establishment of microbial communities and nutrient cycling than mineral fertilizer, and result in a substrate biochemically comparable to that under naturally established revegetation, were supported.