Bronzino Collection: Large Urchin Plant Pot. Urchin garden plant pot hand-made from tin plated copper. Suitable for both outdoor and indoor use, Kenneth Topp's award-winning sculptural cauldrons make tired terraces a thing of the past. Inspired by the round spiny form of a sea urchin, this handmade thorny plant pot has been hand-crafted from tin plated copper. This design is available in two sizes.