Information on plastics. What is safe for food and what is not. -- CAREFUL Plastic that is safe to grow food in/with should have recycling numbers 1, 2, 4 and 5 on the bottom. Plastic with a 3 have PVC in them. In time chemicals leach out contaminating soil, which in turn contaminates the food. Styrofoam is made of plastic number 6 and have cancerous effects, Number 7 contains bisphenol A which is harmful to the behavioral growth of children.