Put all of the ingredients into a large soup pot and stir to combine.
Cover and bring to a simmer over medium heat.
Decrease the heat to medium-low, cover and cook, stirring occasionally, for 35 to 45 minutes, or until the root vegetables and the lentils are soft.
Season with salt and pepper, to taste.
Spoon into deep bowls and serve with a green salad on the side.
Notes
If you cannot find a pre-packaged lentil trio blend, you may use any combination of black beluga, red and/or green lentils. Alternately, you may combine and use two or three of your favorite lentil varieties in this recipe.
If you cannot find fire-roasted tomatoes, you may substitute regular canned diced tomatoes.