We’re pretty sure that the radishes are not yet ripe, based on the size of their leaves.  Still, there’s only one way to tell how they are developing:  Pick one and see what it looks like (I’m not counting ground-penetrating radar or x-ray specs).  We plucked one out of the row of radishes we planted a month ago and were thrilled to see that the radish itself—the globe-shaped part—has formed distinctly, even if it still very small (about 1/8” in diameter).  We added it to our salad and will wait another few days before checking again.