In a large pot over medium high heat, saute the oil, onion, bay leaf and garlic for 5 minutes, or until onions are translucent. Add the peas, barley, salt and water. Bring to a boil and reduce heat to low. Simmer for 2 hours, stirring occasionally.
Add the carrots, celery, potatoes, parsley, basil, thyme and ground black pepper. Simmer for another hour, or until the peas and vegetables are tender.