Combine water, napa cabbage, ginger, and garlic in a large pot and bring to a boil. Reduce heat and simmer for 30 minutes.
Add tomatoes, celery, onion, carrots, dates, and goji berries. Bring soup back to a boil. Reduce heat and simmer until flavors blend and soup is slightly darker in color, about 2 hours.
Remove from heat and let rest for 15 to 30 minutes. Bring back to a boil before serving.
Add sea salt, pepper, and a spoonful of chopped green onion to each serving bowl. Ladle soup into the bowls and stir.
