When you add herbs and spices to vegetable soup, you build flavor, which means you can cut down on the salt in the soup. Add fresh herbs toward the end of the cooking process so their flavor stays bright. Dried herbs and spices can be added earlier, but don't use too much as the flavors may intensify as the soup cooks.
Tomato Soup Variety
Spices and herbs that complement tomato-based vegetable soups include herbs that are traditionally used in tomato dishes, such as basil, oregano, parsley and rosemary. These are particularly good in Italian soups, such as minestrone with pasta and beans. Tomato-based soups start with a strong flavor, so accent them with spices such as black pepper and hot pepper flakes for added heat.
A New Twist on a Classic
Classic vegetable soups, which start with a vegetable or chicken stock and have vegetables added in, generally use herbs such as thyme, parsley and bay leaves. These add warm, comforting aromas that are reminiscent of homemade chicken soup. Spice these soups simply with pepper to enhance traditional flavors, or give the traditional a twist with additions like coriander or Chinese five-spice powder. Try some of the less well known herbs, like chervil, savory or tarragon, for an intense vegetable flavor.
Depending on the spices and herbs you use, your vegetable soup can have flavors from many different areas of the world. Add cilantro and chili peppers for a Mexican-inspired vegetable soup, lemongrass for Asian soup, coriander and turmeric for an Indian soup, or smoked or spicy paprika for a Hungarian one.
Keeping It Fresh
Store fresh herbs in the refrigerator and use within a week. For best results, pick them fresh and use them immediately. It's possible to grow herbs indoors even through the winter in small pots on a windowsill. Store dried herbs in a cool, dark place and use them within six months. Buy spices whole and toast and grind them yourself for the best flavor. Use whole spices within a year of purchase.