He was born at Wood Street,
Walthamstow, 12 October 1765, the third and youngest son of
Edward Forster the elder and his wife Susanna;
Thomas Furly Forster and
Benjamin Meggot Forster were his brothers and
Susanna Dorothy Forster his sister. He received a commercial education in the
Netherlands, and entered the banking-house of Forster, Lubbocks, Forster, & Clarke. Forster took up botany in
Epping Forest at age 15. With his two brothers he later cultivated in his father's garden almost all the herbaceous plants then grown, and contributed county lists of plants to Gough's edition of
Camden (1789). He was one of the early fellows of the
Linnean Society, founded in 1788, was elected treasurer in 1816, and vice-president in 1828. With his brothers he was one of the main founders of the Refuge for the Destitute in Hackney Road. ==Death and legacy==