Question
Hi,

We are planning on building a raised bed for a vegetable garden in the backyard and want to use Cor-ten steel (designed to rust and applicable for roofing and siding).  We have a modern house and would love to have our vegetable garden to match our house.  However, I am wondering whether the rust would harm the vegetables we grow in the box.  We are in Southern California (zone 9-10) and will grow tomatoes, peppers, herbs, cucumbers, eggplants, and green beans (well, that's the plan so far, these are the vegetables we like).  I have never grown anything other than cacti/succulents, so any help would be GREATLY appreciated.  

Thanks!
Joo

Answer
Joo:

I believe that cortin steel is made from using acid to etch the beautiful color into the steel. The exterior of the US Steel Headquarters in Pittsburgh is made with cortin. In addition to being beautiful it is very expensive. Use the cortin steel outside for looks and use wood as a liner. This way, residual acid will not come in contact with the roots of the plants. Now, if you wash the cortin surface good with a lime solution it will reduce the acid surface and you probably can have it coming in contact with the soil and plant roots without fear of root damage.

Hope that this helps.

Best wishes.

Don