1793, he and Andrew Ross established a garden at Corcondah, where they worked on sugarcane and indigo. He also studied the prospects of introducing sago and other food crops to help alleviate the effect of famine. He was invited to fill the position of Superintendent at the Calcutta Botanical Garden where the death of Colonel Robert Kyd had created a vacancy. He made rapid progress and acquired a good reputation and was later invited by the government of Bengal, to take charge of the Calcutta Botanical gardens from Colonel Robert Kyd in 1793 as Superintendent of the Company garden at Sibpur near Calcutta. A catalogue of the garden was made in 1814 – Hortus Bengalensis. He was succeeded by Francis Buchanan-Hamilton. He had sent many illustrations to Sir Joseph Banks, who in May 1795, started publishing Plants of the coast of Coromandel in 3 volumes with over 300 drawings and descriptions of plants. The last part was published in March 1820. The names of the local artists who produced the botanical illustrations were not recorded. He meticulously collected vast amounts of meteorological data for years, and is considered as a pioneer in the collection of tropical meteorological data, to an extent unrivalled elsewhere until the 1820s. He had begun collecting detailed meteorological data as soon as he set foot in India, at Madras, and is known to have taken measurements three times a day, using Ramsden barometers and Nairne thermometers, made by then reputed scientific instrument makers, Jesse Ramsden and Edward Nairne. He trained under John Hope, who was the curator of the Edinburgh botanical garden as well an experimental physiologist. Roxburgh's interest in systematic meteorology may have stemmed from the influence of John Hope as well as his experiences at the Royal Society of Arts which, in the early 1770s, was greatly influenced by the climatic theories of Stephen Hales and Duhamel du Monceau. Such detailed measurements over many years led him to form an opinion on widespread famine and climate change in the empire. He became a member of the Asiatic Society, to whose Transactions he contributed, from time to time, many valuable papers. Amongst these was one of singular interest on the lacca insect, from which the substance lac is made. In 1813, he returned to Scotland due to poor health. To recuperate from his illness before continuing his voyage to Scotland, he stopped at Saint Helena