Hi Julie, Low acid foods like your soup require a pressure canner to heat the food to temperatures around 240*F which boiling water bath canning is not recommended for since water boils at around 212*F which is substantially lower than the recommended temperature for vegetables which is necessary to kill harmful bacteria.
Low Acid Foods include vegetables, soups, stews, meats, poultry, seafood and tomato or vegetable mixtures or sauces.
You can check out more info on low and high acid foods at Bernardin's site www.homecanning.com
Hope that helps and maybe there is someone else who can give you some more info to. I am new to canning with a pressure canner myself and last years veggies were the first ones I pressure canned with the help of a friend : )
Blessings,
HuberHof

Jeanette's right!! I bet you didn't think I knew about canning, did you?? Well, remember we had a garden for several years when I lived in Quail Run and hope to get one back And We canned green beans and froze Limas!! And Corn off the cob!! HEEHEE....my little secret..... remember Im a country girl.... anyway, you DO need a pressure cooker( canner) to seal your jars. You can get them a our famour "Target". I just saw one last week when shopping. I always have just used my mom's. have fun canning.