Today's Haycast kicks off with the sounds of Hay, accompanied by haunting kora music from Seckou Keita.
In the programme, Claire Armitstead talks to writer Colin Tudge and John Reader, who has written a book extolling the virtues of the potato. We also visit one of Herefordshire's most lovely gardens to discuss rhododendrons and other 18th century imports with Andrea Wulf, author of The Brother Gardners: Botany, Empire and the Birth of an Obsession.
Tudge is in Hay to talk about trees, but his interests range widely over the environment and the problems of feeding the world. On the eve of next week's meeting of world leaders in Rome to discuss the current food crisis, he gives them advice on averting global catastrophe.
Reader's book, Propitious Esculent, tells the story of how a humble south American tuber became the world's most efficient food source. He discusses the belief, strongly held by some scientists, that the potato might yet be the key to the survival of the human race.
Plus: Sarfraz Manzoor asks if Jeremy Clarkson is for real, and Matt Seaton sets off on a cycle ride in the Black Mountains with Jeremy Whittle, who tells him all about the drug scandals blighting the Tour de France.
