Marijuana growers crave this Brigham Young University student’s organic fertilizer

Joseph Walker says he’s killed his weight in worms.But after a dozen tries, Walker believes he’s come up with an effective process for encouraging worms to eat — and more important, to poop — and then converting their teeny droppings into an organic fertilizer.The Brigham Young University student’s main customers are commercial growers of marijuana, a market that’s exploding as more states approve pot use for medicinal or recreational purposes.“This mark