This article titled "How To Grow Sprouted Onions" at Alternative Gardening talks about exactly that. I had no idea. All this time, if I didn't eat an onion in time, I would simply plant the whole thing as-is in the soil.
Forcing tulips in water is a fun, easy, and a unique way to grow tulips that most people have not seen before. Showing the natural beauty of the bulb is a pure, modern, and minimalist approach to floral design.