Clean the lentils and remove any small stones that might be among them. Soak them in water for 10-15 minutes, then drain.
In a clay pot add the lentils, carrots, tomatoes, onions and water.
Gently simmer the soup for 1 to 1-1/2 hours over medium heat until the lentils are cooked through. Lentils shouldn't be eaten undercooked, but it's also important not to overcook them. They should be soft enough to give the soup a creamy texture.
Season the lentils after they're cooked or they will turn hard. After the soup has simmered for 1 to 1-1/2 hours, remove it from the heat and add the olive oil, wild garlic,celery, red wine vinegar, and season with Greek salt to taste. Serve hot.