Mushroom Barley Soup

1 cup pearl Barley
juice of 1 lemon
2 tablespoons extra-virgin olive oil
1 small onion, diced
1/2 teaspoon sea salt
1-1/2 cups peeled and finely diced carrots
1-1/2 cups finely diced celery
1 parsnip peeld and diced
1/4 pound white mushrooms, thinly sliced
1/4 pound shiitake mushrooms, thinly sliced
2 cloves garlic, minced
1/4 teaspoon dried oregano
1/4 teaspoon dried thyme
1/4 teaspoon dried caraway
pinch of freshly ground pepper