Born in London, Blow studied at St Martins School of Art and then the RA Schools, finishing up her student days at the Academie della Belle Arte, Rome in 1948. She taught at the Royal College of Art, London. After some further travelling she settled in London before arriving in West Cornwall, to stay a year in a cottage at Tregerthen to be near Patrick HERON and his wife Delia. Other close friends were Roger and Rose HILTON. Latterly she became a member of the Hypatia Trust and made a significant donation to the establishment of the WCAA in Penzance.
Over the remaining years she lived and worked both in London and in West Cornwall, associating herself with several societies in both places. In the 1990s she acquired one of the Porthmeor Studios, and from that studio came her first painting for the Tate Gallery St Ives (Porthmeor Beach exhibition). She joined the Penwith Society in 1958, and was elected an associate of the RA in 1971 (RA 1978).