Photo of petunia 

Several of the flowers in AeroGrow seed kits are edible: petunia (pictured), dianthus, lavender, marigold, calendula, snapdragon, and geranium. Their flavor is mild and, well, flowery, and the petals make a bright garnish on a green salad, cooked rice or mashed potatoes, or any other dish you want to dress up with color.  Don't use too many or they can look overwhelming, but don't be afraid of them, either - people have been using  flowers as a garnish for milennia!