As designers put the finishing touches to their gardens ahead of this week's horticultural showcase, Diarmuid Gavin, Alan Titchmarsh, Monty Don and Rachel de Thame learn about the months of planning for the five-day event. Coverage starts tomorrow at 2.40pm on BBC1. www.bbc.co.uk/gardening
How does Chelsea score?: page 16; Britain's worse gardening crimes: p20