Preheat your oven to 425°F. Toss the fennel wedges and radishes with olive oil and a generous pinch of salt on a sheet pan. Roast for about 15 minutes, then add the asparagus, drizzle with a little more oil, season lightly, and continue roasting for another 15 minutes until tender and caramelized.
While the vegetables roast, bring water and a pinch of salt to a boil in a saucepan. Add the farro, reduce to a simmer, and cook for about 25 minutes until tender but pleasantly chewy. Drain any excess water and let it cool slightly.
In a food processor, combine Greek yogurt, parsley, basil, chives, lemon zest, lemon juice, and Dijon mustard. Blend until smooth and creamy. Taste and adjust salt or lemon if needed—the sauce should be bright and fresh.
Toss the warm farro with most of the herb yogurt sauce until well coated. Transfer to a serving bowl and arrange the roasted vegetables on top. Finish with extra chives, fennel fronds, and a squeeze of lemon for a final burst of freshness.