The United States Department for Agriculture (USDA) plant hardiness zone map, 1990
If you blog about gardening here in Britain, it's not too long before you encounter your American and Canadian cousins who all talk about which zone they garden in as if it was as natural as breathing. Strike up a conversation with any of these gardeners and it's not long before you're asked what zone is your garden? Luckily when I was first asked this last year, I had just been looking at the above map in The Essential Design Workbook by Rosemary Alexander.
For an explanation about these zones and which one I placed my garden in, without having to read the above book, hop on over to Veg Plotting for the answers.
Many thanks to Denise, Gerald and the rest of the ABC team for ensuring we all made it here to the end of ABC Round 3 :D