Raven was born in Cambridge, the daughter of John Earle Raven (d. 1980), a classics don and Senior Tutor at King's College, Cambridge, by his wife Faith née Smith (Constance Faith Alethea Hugh Smith), a daughter of Owen Hugh Smith (1869–1958).
She is married to writer Adam Nicolson, 5th Lord Carnock, and has two daughters with him, plus three stepsons from his previous marriage. Her family's move to a small farm in Sussex was depicted in Nicolson's book Perch Hill: A New Life.
She now runs a garden and cookery school at Perch Hill, and is a guest presenter on BBC Two's Gardeners' World. She writes a weekly column for The Daily Telegraph. The celebrated gardener Christopher Lloyd, a near-neighbour of the Nicolsons at Great Dixter, described Raven in the mid-1990s as "really energetic and creative ... promot[ing] a more dynamic and showy style of gardening than has been fashionable for many years".
Raven's publications include The Cutting Garden, The Bold and Brilliant Garden, The Great Vegetable Plot and Sarah Raven's Garden Cookbook (U.S. title: In Season) which was named Cookery Book of the Year by the Guild of Food Writers in 2008. In 2011, she published a monumental book on Wild Flowers, with photographs by Jonathan Buckley, who has worked with her on most of her books. A BBC2 television series called Bees, Butterflies and Blooms, focusing on the national decline in pollinating insects and championing nectar-rich flowers as a way of saving them, was broadcast in February 2012. She presented an episode of Great British Garden Revival which aired on BBC Two in 2014. Sissinghurst: Vita Sackville-West and the Creation of a Garden was published in November 2014.
- Her middle name Clare is found at Lundy, Darryl. "p. 20654 § 206532 database". The Peerage..
- Date of death taken from "A Rum Affair" New York Times Book Review], which has the first chapter of Karl Sabbagh, A Rum Affair: A True Story of Botanical Fraud, Farrar, Straus and Giroux
- "Gardener's world". The Guardian. London. 3 November 2005.
- Lundy, Darryl. "p. 17294 § 172931 : Constance Faith Alethea Hugh Smith". The Peerage.
- Andrew Purvis (16 November 2008). "Christmas at Sissinghurst: While visitors to the gardens peer through the windows, Sarah Raven cooks an early Christmas lunch in her national trust kitchen". London: The Observer: Observer Food Monthly. Retrieved 23 November 2008.
- BBC - Press Office - Sarah Raven. The original of this reference is no longer available, but the link is to an archived version at the Internet Wayback Machine. Her current BBC biography has no educational background for her.
- Penguin Books, 2000. ISBN 0-14-029089-3
- BBC - Gardening - TV and radio - P to R
- Letter to Beth Chatto, 29 October 1996 in Chatto & Lloyd (1998) Dear Friend & Gardener
- Guild of Food Writers Archived 25 March 2009 at the Wayback Machine
- Cumming, Ed (12 November 2013). "Time for a Great British Garden Revival". The Daily Telegraph. Retrieved 16 November 2013.