Mix olive oil, garlic, lemon juice, salt, and pepper together in a bowl and set aside.
Combine chicken broth and farro together in a large sauce pan or wok; bring to a boil. Reduce heat to medium and simmer until farro is tender and the broth is absorbed, 20 to 25 minutes.
Stir olive oil mixture into farro until farro is coated. Add spinach to farro mixture; cook and stir until spinach is heated, 2 to 3 minutes. Sprinkle feta cheese over farro and spinach and stir until cheese is incorporated.