Brown and white peeling skin Textures, subtle tones,pleasing colours, repeating shapes and the white garlic that one sees first in the very centre. Nice composition.
My first thought is this is a little too stock-photography like for my tastes...but the skins and roots add nice textures and bring more interest. Nice job!
Would be a great stock shot if the DOF was crisper and some of the onions were fresher, not mouldy under the skin. Ambient lighting is perfect however, and the idea is a good one!