Preheat oven to 400 degrees F (205 degrees C). Line a large baking sheet with parchment paper or a silicone mat.
Rinse the delicata squash, and cut it in half, lengthwise. Remove all the seeds with a spoon, and slice it into 1/3-inch slices. Toss the squash, sliced carrots, and onions with 1 and 1/2 tablespoons of olive oil and a pinch of salt. Spread the vegetables over the lined baking sheet in a single layer. Roast them for 30 minutes.
Rinse the farro. Place it in a medium saucepan with 2 and 1/2 cups of water and cook over medium-high heat. Once the water boils, stir the farro, turn the heat down to medium, and let the farro cook until the water has evaporated. Stir the grains occasionally. The farro should cook in 25 to 30 minutes.
Prepare the pesto by blending the carrot tops, basil, parmesan cheese, walnuts, olive oil, water, and salt in a food processor until smooth.
When the farro is cooked, pour it into a large bowl. Add the diced red pepper and pesto and stir until well incorporated. Fold in the roasted vegetables. Serve the farro in bowls.
Refrigerate leftovers in an airtight container.