We just bought a house and our back yard has septic tank/large leaching field, so limited space for veg garden. If I make these elegant raised beds I'd still need to line them with something so the roots of veggies don't reach down into leaching field. We're in greater Boston area. Any suggestions gratefully accepted. Also would 4 of these beds, tho' smaller, work for 4 corners of a grape arbor? That has always been a dream of mine to have... Many, many thanks.