I needed a radish to complete my daughter's Luna costume for ComiCon. The only 3d model of a radish I could find was in this group of vegetables:

https://grabcad.com/library/vegetables-1

The leaves, unfortunately, were too difficult to print. So I removed them and used part of the leaf coaster to replace them. You'll want to scale it up to whatever size you need... the photos are at a 10x scale. The radishes were then painted and glued to the buttons with hot glue. My spouse thought they looked better with half the leaves broken off on half the radishes (so she broke them off).