Prepare all vegetables by washing, peeling, and cutting them as specified in the ingredients list.
In the crock pot, combine the vegetable broth, diced tomatoes (with juice), diced onion, minced garlic, sliced carrots, diced celery, diced zucchini, chopped green beans, and corn.
Add the dried thyme, dried basil, salt, and black pepper to the vegetable mixture; stir well to combine.
Cover the crock pot with the lid and set it to cook on low for 6 hours.
If using leafy greens, add them to the soup during the last 30 minutes of cooking to keep them vibrant and tender.
When the cooking time is complete, stir the soup once more before serving.