Heat your oven to 400ºF.
Add the farro and water to a saucepan and bring to a boil. Cover and reduce heat to low; simmer 10 minutes. Remove from heat and let sit 5 minutes.
Arrange the carrots, asparagus, radishes, and leek on a baking sheet Drizzle with olive oil and season with salt and pepper. Roast 15-20 minutes, or until the carrots are tender. Slice the leeks crosswise.
While the vegetables cook, prepare the pesto. Add the pistachios, olive oil, and basil to a blender. Blend on high until smooth. Add the parmesan and pulse until combined. Season with salt and pepper. Thin the pesto with additional oil if desired.
To serve, stir 1 Tablespoon of the pesto into the farro, then divide the farro between four bowls. Top with the vegetables and another dollop of pesto.