I grow this wonderful sour herb in my garden. You can buy seeds and plant in your garden and they will come up every year. I always freeze bags of sorrel for the winter because my son loves this soup. Pick the leaves, wash well a few times and chop and put in containers or freezer bags. When you are ready just pop them in the soup from frozen state. If you don’t have enough sorrel use 4 cups tightly packed chopped sorrel and 3 cups tightly packed chopped spinach or Swiss chard and juice of one lime. Adjust the sorrel to your taste. If you like it less sour then by all means use less or combine it with spinach or Swiss chard.