F.W. Reitz senior, agriculturalist and politician, was the son of Jan F. Reitz and his wife Barbara J. van Reenen. One of his brothers, Jacobus Johannes, was a lieutenant in the British navy and accompanied Captain W.F. Owen* on his hydrographic surveys of the African coasts. On 9 July 1833 F.W. married Cornelia M. Deneys, with whom he had four sons and eight daughters. Their third son, named Francis William like his father, later became president of the Orange Free State.
After completing his schooling in Cape Town Reitz left for Edinburgh, Scotland, in April 1826, to study agriculture. After completing his studies he visited the Prussian royal stables at Dresden, Germany, merino stud farms in Nantes, France, and irrigation projects in Italy. In 1835 he established himself on the farm Rhenosterfontein, on the Breede River, where he farmed for more than 30 years. His education and experience in Europe enabled him to become the most progressive Cape agriculturalist of his time. Throughout most of his life he remained interested in scientific agriculture and kept in touch with developments in the breeding of sheep and horses. He became one of the two managing directors of the agricultural firm Reitz, Breda, Joubert and Company, and was the senior partner from 1847 until the partnership was dissolved in 1851. Though his farm was initially devoted mainly to horse-breeding he was more interested in sheep and developed an excellent merino flock.
Reitz played a leading role in founding the second Swellendam Agricultural Society in 1842. He served as its first secretary until at least 1857 and regularly published the society's reports, announcements and advertisements in the South African Commercial Advertiser. In 1834 he started a book club in Swellendam, which developed into the local library. He also acquired a considerable private collection of agricultural books and gained a reputation as a person with a comprehensive knowledge of agriculture. Around 1858 he served on the management committee of the short-lived Swellendam Literary Society. The next year he chaired a committee which investigated the financing and cooperation between the 24 agricultural societies existing in the Cape Colony at the time. The committee's report was published in the Cape Monthly Magazine (June 1859) and in the Kaapsche Grensblad (4 June 1859). In 1862 he exhibited the products of the Cape Colony at the International Exhibition held in Kensington, London.
Reitz's publications included a pamphlet, Observations on the merino; containing a brief account of the methods by which that animal has been brought to its present state of perfection in Germany; and intended for the consideration of wool-growers at the Cape of Good Hope (Cape Town, 1834, 16p). In 1849 he was co-editor of the short-lived journal South African Agricultural News. On 1 May and 15 May 1857 he delivered two lectures reviewing Cape agriculture before the Cape Town Mechanics' Institute (a society for the promotion of adult education), in which he deplored the lack of organised agricultural research at the Cape. The lectures were published in the form of a pamphlet entitled Cape agriculture in Cape Town that same year. He also contributed several articles to the Cape Monthly Magazine. For example, in a letter on "The Angora goat and the Swellendam Agricultural Society" (April 1857, Vol. 1(4), pp. 158-166) he drew attention to the role played by that society in the introduction and promotion of Angora goats. In "Irrigation" (1857, Vol. 1, pp. 135-142, 223-230, 296-304) he discussed irrigation works in various parts of the world and irrigation possibilities in South Africa. Other articles dealt with "Salt pans and salines" (1859, Vol. 5, pp. 275-279), and "Agricultural societies" (1875, Series 2, Vol. 11, pp. 261-264). In the latter he proposed the establishment of a board of agriculture and greater government support for agricultural societies.
Reitz entered politics during the anti-convict agitation in 1849. The Governor of the Cape Colony appointed him to the Legislative Council in June 1850, but he resigned three months later in protest against the delay in drafting a constitution for representative government. However, when the Cape Parliament was established in 1854 he was one of its members, serving for ten years. He publicly supported the separation of church and state and his views on this matter were not well received by the local clergy. Later he served as a member of Parliament for Swellendam from 1869 to 1873.