Marijuana is likely one of the most interesting and rewarding plants to grow. Most people think that old mattresses are a problem. The mattresses just stack up in the garage or get thrown out. There is no disposal mechanism for Polyurethane foam mattresses. But they can give everybody their own garden. So how to grow things in polyurethane foam? With your old mattress you can grow stuff all over, and you we will be able to turn your old bed into green cash. I have been to a landfill site and seen a tomato plant growing in an old sofa.