Today, seed plants make up about 90 percent of the world's flora. But that wasn't always the case. Today on Please Explain, Thor Hanson, author of The Triumph of Seeds: How Grains, Nuts, Kernels, Pulses, & Pips Conquered the Plant Kingdom and Shaped Human History, describes the path that seeds have paved through evolution, natural history, and human culture, and examines the traits and habits that have allowed seeds – and the plants that bear them – to be successful, and to transform the planet. Plus, Gerard Lordahl, Greening Director of GrowNYC returns to the show to offer advice on planting seeds at home!