The tiles that Molly Grothaus used for growing bulbs were *flue* tiles, roughly 18" x 10" rectangular cross section, not the small 6" diameter drain tiles. Her husband was a builder or contractor so she was able to get these in quantity at a reasonable price. Butted up against one another, frost wouldn't have penetrated from the sides except around the edges of the assemblage. Anyone living in an area where new residential construction usually includes a brick fireplace with a brick chimney can probably still buy these. -- Rodger Whitlock Victoria, British Columbia, Canada Maritime Zone 8, a cool Mediterranean climate on beautiful Vancouver Island http://maps.google.ca/maps/…