NSALG assistant national secretary Donna McDaid said: "Geoff was a great advocate of the allotment movement as well as a great boss. Gardening was his main interest and he would bring in a variety of vegetables to the office, and also lovely jams and chutneys that his wife Liz made. He will be sadly missed by everyone."
Last year his book Teach Yourself Allotment Gardening was published as part of the "Teach Yourself" series. Stokes did not tend an allotment himself as he had a garden at his Northamptonshire home.
He is survived by his wife and two adult children.