I have moistened vermiculite in trays under my fluorescent lights and placed the newly potted rooted leaf in tray and covered it with an upturned glass container to maintain the humidity that violets like. Under these conditions the roots should grow quickly and I should see a baby plant or plants within a few short months. I suspect had I placed the cut leaf in a soilless medium and let it root in that, enclosed in an inflated plastic bag, I might see babies sooner.