Potash was a key input into early modern British industry. It was used as a source of alkali, predominately in the making of soap for washing woollens, and the bleaching the linen. Although an essential intermediary input into manufacturing processes through precursors to the modern chemical industry, the trade in ash and its ecological impact have gone almost entirely unnoticed by both economic and environmental historians. This article sets out the scale of the trade and its organisation reaching to regions of supply in the Baltic and Russia, before a rapid switch towards North American suppliers after 1760. Knowledge of the potash trade brings a new international dimension to our understanding of the scope of the ‘organic economy’, as a product that accounted for the largest share of ‘ghost acres’ abroad used to underpin British industrialisation and whose wood requirements came to far exceed the production of wood within Britain. Data on the ash trade also provides an indicator for the scale of industrial output, and relative size of the textile finishing sector in England and the Netherlands that may modify our understanding of the relative fortunes of industries in both countries