Geddes was born in Cheam in Surrey and attended school in Eastbourne.[1] She studied at the Westminster School of Art in London, where she was taught by both Walter Bayes and Mark Gertler, from 1930 to 1936.[2][3] Geddes began exhibiting in group shows while still a student and in 1938, was elected to the National Society of Painters, Sculptors and Gravers.[2][4]
During World War II, Geddes worked as a draughtswoman in the Fire Service Department of the Home Office.[4] After the war, she resumed her exhibition career, showing regularly with the London Group, the New English Art Club, the Society of Women Artists and at the Royal Academy.[2] The Leicester Galleries and the Redfern Gallery also displayed her work.[4] Her first solo exhibition was hosted by the Artists' International Association in 1950.[1] Further solo exhibitions at the Halesworth Gallery in Suffolk and at Teddington in 1973 followed.[1] From 1951 to 1955, Geddes served as the chairperson of the Women's International Art Club.[4]
Over time, Geddes's painting moved from figuration to abstraction.[5] In 1996, Geddes, with Alzheimer's Disease retired to a nursing home. Retrospectives of her work were held at the Woodlands Art Gallery in London in 1998, and at Camden Fine Art in Bath, the following year.[1][3]