Saute onion in oil until soft, along with bay leaf and celery seed. Stir in peas, barley, and limas. Add 10 cups cold water and bring to a boil. Cook 1 hour and 20 minutes.
Add salt, pepper, basil, thyme, carrots, celery, parsely and potato. Turn heat down as low as possible and simmer another 30-45 minutes. Thin with additional water or stock if necessary.