In a large bowl, place the broccoli, blueberries, red onion, cranberries and sunflower seeds.
In a small bowl, mix the apple with 1 tablespoon lemon juice; add this to the large bowl with the rest of the salad.
In another small bowl, whisk together all the ingredients for the yogurt dressing.
Pour the dressing over the salad and mix; you decide the amount of dressing.
The salad can be served immediately or refrigerated for up to 3 days in the refrigerator.