Some have said there could be contamination, but vegs. are grown in boxes, which are probably potting soil and should have no contact with underlying soil. I would say that an easier way might be just to leave asphalt and use boxes on top. … And yes soil has been tested in some parts of the site, and yes there is a layer of cardboard/newspaper, then compost and sil and more compost and soil made on site and topsoil provided by the Greenthumbs project I think. …

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