1 cup water, or more as needed
1/4 cup frozen blueberries
1/4 cup seedless green grapes
1/2 green apple, cored and chopped
3 frozen strawberries, or more to taste
1 (1 inch) piece peeled fresh ginger, cut into thirds
1 tablespoon agave nectar
Blend water, blueberries, grapes, apple, strawberries, ginger, and agave nectar together in a blender until thick and slushy.