Raw Steel Raised Garden Boxes
I have a sloped yard and I am having some Raw Steel Raised Boxes fabricated that will also act a about 3 ft retaining walls. The fabricator recommends waterproofing and insulating the inside. I plan to grow vegetables in the boxes and I am worried about chemical and toxic leaching (he originally suggested I coat the inside with tar. So...
1. Do you think the boxes need insulation? They get several hours of direct hot west sun. Will they get too hot to grow veggies? What non-toxic material could I use to insulate? I am thinking maybe cork
2. I know waterproofing will extend the life of the boxes, but if I didn't waterproof, how long will raw steel last in an outdoor environment, with soil behind the steel? It also snows where I live.