Eric Robson chairs the popular horticultural forum. Matthew Biggs, Pippa Greenwood and John Cushnie join members of the John Innes Conservation Society in London. They find about about the man who posthumously founded the horticultural institute which is responsible for creating the compost which bears his name. Also, after Buckingham Palace joined the RHS Grow Your Own campaign, Matthew is invited to the Queen's allotment for a review of its progress so far. Including Gardening weather forecast.