Heat the olive oil over medium heat in a large pot. Add the diced onion, carrots, celery, and sauté for about 3 minutes or until they soften. Add the garlic and cook for another minute until fragrant.

Add the bell pepper and zucchini. Stir and cook for 5-7 minutes until the vegetables soften.

Add the farro or barley, tomato sauce, water, thyme, oregano, cumin (if using), and salt. Stir to combine.

Bring the mixture to a boil, then reduce the heat to low and let it simmer, covered, for 25-30 minutes, or until the farro or barley is tender and the flavors have melded.

Stir in the fresh spinach and cook for 3-5 minutes until the spinach wilts. Add a lemon juice of ½ lemon for brightness if desired.

Taste and adjust salt as needed. Ladle into bowls and enjoy your warming, nutritious vegetable soup!