Heat 1 cup of watermelon juice. Add the gelatin to the hot watermelon juice and stir to dissolve. Add the rest of the juice and stir. Pour the gelatin mixture into 4 soup plates. Refrigerate for at least 2 hours, or until the gelatin is set.
Garnish each plate of gelatin with a bit of each spice, placing the vanilla seeds at 12 o'clock, mint at 1 o'clock, basil at 2 o'clock, and so on.