Absolutely not - research shows that soil stays at an ideal and more even temperature in a galvanized bed when compared to concrete, dark plastic and wooden beds that will soak up the summer sun during the day and stay hot into the evening. It's all because of the greater albedo (search "albedo" online for lots of good information on this subject) found with galvanized steel. For garden beds, studies have shown that ambient temperatures are optimal with galvanized material as compared to other material options. The steel material is reflecting off the heat when other materials (namely concrete) absorb all the heat during the day and then remain hot throughout the evening. Additional research has shown more benefits of gardening with galvanized material. These include improved fruit blush color (finish and sweetness), more even fruit maturity, improved fruit set (return flowering), increased fruit size and increased total yield.