Sealing Concrete Raised Vegetable Beds
I bought a house last year that has 5 large raised gardening beds made of concrete block. The exteriors are painted. Living in Arizona, there is irrigation to each bed. The water leeching out of the beds causes the paint to flake and peel. We have been doing an extensive remodel on the house and last November I hired a company to come out, remove the soil, coat the insides of the beds with a waterproof coating, refill the beds with half of the previous soil and bagged organic soil I purchased at a nursery. They left the bottoms uncoated to allow for drainage. The beds are sitting on top of soil. My daughter became very ill at her University. I left town for 5 days to take care of her and when returned, the work had been done. The company left their containers of sealant near my garbage bins and I was alarmed when I found them. Roofing tar. I immediately researched the ingredients, reading MSDS sheets and as much info as I could find online. There were 3 ingredients, only 2 were okay, one was not and was actually banned for use in CA as cancer toxic. I called the company, had them come out and went over it in detail, just as I did when I hired them. They said they always use this item when waterproofing beds. I gave them copies of the MSDS I pulled and asked them if they would eat vegetables grown in planters where this was used. They felt that if the tar was dry, it couldn't leech into the soil and eventually into the plant roots. I don't care. I got my money back and now am revisiting this again. Arizona's climate is very harsh in the summer and plastics become very brittle in the heat and would not due to line these beds. I am hoping someone can suggest something I can use to recoat over the tar to make my beds safe.