Hey hey hey! Who do I find asking qs about cooking but our very own mithy! I am sure KV is better at answering this since she actually uses vegetable stock regularly. I can only tell you that many store bought stock - vegetable or chicken have very high sodium content (they add salt to make the stock taste almost drinkable plain!). My mom taught me that dhal water, water used to cook vegetables in etc can all be used much like vegetable stock. You can make your own stock as well and freeze them for a couple of months or put it in the fridge for a couple of weeks. Since I am a vegetarian I can give you vegetable stock recipe: Rough chop/medium size pieces carrots, onion (big or small), garlic, radish. You can add beetroot if you want red color, cauliflower, peas, beans - pretty much any vegetable except for greens and tomatoes. Carrot, onions and garlic are the most important here however. Take a big stock pot or big pal pathram and throw in the veggies, add water to cover them and a little bit more. You can throw in some corander leaves, parsley or simply add jeera, some whole black pepper (not too much as you don't want to make it very spicy), small piece of cinamon, 1 or 2 clove. Allow the water to come to a boil, then turn down the heat to very low. Check to make sure the water is not completely evaporated - you may have to add a tumbler of water sometimes. Let this pot simmer for about 35-45 mins. It will smell cooked and very fragrant. Drain the water into another vessal. This water is stock. The veggies will have lost all of thier flavour and cannot be really used for cooking again. But you can use them as good fertilizer for your garden. I believe chicken stock is done somewhat similar using large pieces of chicken including the bones. I am not sure. I hope this helps.
I will look for Knorr next time. I tried Maggi. It was okay. But homemade stock tasted better than Maggi.