Michel Adanson was a precocious young botanist when he traveled to Senegal aboard a French Indies Company ship in 1749. He spent more than four years in Africa amassing thousands of specimens and reams of notes and maps, while struggling to get the necessary resources for his work from local Company officials. As evidence of the commercial utility of his natural history, he embarked on an experimental program to test and compare locally grown species of indigo, producing samples of pigment and dyed cloth in his rudimentary African “laboratory”. Dyed in Africa, with indigo produced by a French naturalist, samples sent back to France incorporated Parisian botanical knowledge, the know-how of at least one indigo worker brought to Senegal from Saint Domingue, and local West African knowledge of cultivation and dyeing techniques. This paper excavates the layers of different kinds of knowledge and practice that went into producing these samples, and explores the imagined payoff of Adanson’s indigo experiments in the context of French imperial ambitions. Though Adanson’s grand plans for Senegalese indigo did not come to fruition, his attempt to parlay his specialized knowledge into a grand transatlantic scientific expedition and a revived French colony in South America expose the tenuousness of the ties binding scientific knowledge to a fragile empire reeling from the losses of the Seven Years’ War.