Enclosed is a picture of radish. I pull a few out. But there are no
Radishs at the end of the stems. Too early to harvest?? <a href="http://img170.imageshack.us/my.php?image=radisheskn6.jpg" target="_blank"><img src="http://img170.imageshack.us/img170/6907/radisheskn6.th.jpg" border="0" alt="Free Image Hosting at www.ImageShack.us" /></a>

If there is a little pink area at the end, then no, they aren't ready yet. You can usually see them popping up from the earth when they are ready.

Also the bottoms of the stems get very deep pink/red this helps me out. And as tickle said they will bulge up out of the ground. Some people like them to be the size of a golf ball, but my mom let them grow to the size of a tennis ball.

You may pick and eat a radish at any size you desire. Large rdishes tend to become bitter and woody. However, if radishes are planted too close together they will not develop a "globe"shape.