Absolutely! Frozen vegetables are a convenient option for soups. Here are some tips to keep in mind:   Thaw or Partially Thaw. Frozen vegetables tend to release excess moisture when cooked. To avoid a watery soup, thaw them completely or partially before adding them to the pot. You can thaw them in the refrigerator overnight, under cold running water for 15-20 minutes, or in the microwave using the defrost setting.   Cooking Time. Frozen vegetables cook faster than fresh. Adjust the cooking time accordingly to avoid overcooking them.