Vancouver Sun: Keira McPhee’s response to the world food crisis is to pave over her front lawn. Not with asphalt, but with an initial application of “weed tea” to help fertilize the ground. “No marijuana in it!” she says, standing in gumboots outside her blue stucco home on Adanac Street in east Vancouver. “Buttercups and stuff.” Next came a layer of cardboard — a source of fibre and carbon — followed by at least 15 centimetres of organic matter that included …