Molineux was born in
Brighton, England, to Martha (c. 1809 – 23 March 1882) and Edward Molineux ( – 30 May 1876), and left for South Australia at six years of age with his parents in the barque
Resource, arriving in January 1839, and for a year lived on Buffalo Row. His father was a bootmaker who hoped to make a living at his trade, but was forced by circumstances to take a position at the makeshift prison behind
Government House. They later had a farm on the
River Gilbert, near
Riverton. His first employment on leaving school was on a farm at
Klemzig, after which he was apprenticed as a
compositor to
George Dehane. In 1851 he joined the great exodus to the goldfields of Bendigo, where he made a modest living, after which he took up farming in the region of
Riverton. He began contributing to the gardening pages of the Adelaide newspapers, and in 1875 he established the magazine
The Garden and the Field, as a successor to
Edward William Andrews'
The Farm and Garden. The venture was successful, and he developed a devoted readership, continuing as editor until around 1893, when he accepted the position of general secretary to the Central Agricultural Bureau. He helped develop tomato growing in South Australia, also oyster harvesting, having developed a trawl net for studying their habits. In 1890 Molyneux and J. Orchard presented a paper "Harvesting of Wheat Crops" to the Agricultural Bureau Congress. He retired from the public service in 1902 and was appointed to the Council of Agriculture, and its successor, the Advisory Board of Agriculture, where his wealth of knowledge and experience was appreciated by practical farmers. He was prominent in urging development of forests for future timber requirements. He was an advocate for the use of fertilsers, fallowing, and mixed farming. He recommended
Bordeaux mixture to prevent fungus diseases such as
scab in apples and pears and
shothole in apricots; and arsenical sprays to combat
codlin moth. ==Recognition==