Jonathan Harrington grew up on a small farm in mid-Wales before studying agriculture at Harper Adams Agricultural College in the mid-1970s. He previously worked for Fisons Fertilizer before heading to Southern Africa, where he worked on a number of farms growing maize, tobacco, bananas, potatoes and wheat.
Upon returning to Britain, he worked as a technical adviser for Bayer Crop Protection, then in the agricultural supply trade, before setting up his own consultancy practice, Optima Excel Ltd. His company also runs a technical inquiry helpline for agrochemical manufacturers.
Harrington is a visiting lecturer at the Cardiff University School of Biosciences, teaching undergraduate plant biochemistry and courses on crop agronomy for budding agriculturalists. He is also a consultant to the Welsh Assembly Government, which offers subsidized plant nutrient advice to Welsh farmers through approved advisers.
He is particularly interested in educating the general public agricultural science and has been offering farm walks at The Hay Literary Festival since 2005.