I challenged readers to a "Biggest Tillage Radish" contest this fall. I planted a few seeds in my garden in August. The plants are up and growing. I'll wait until November to pull them for measuring. The goal of tillage radishes really isn't to grow the biggest, but to grow a uniform cover crop. They break up soil compaction. You can see more info here: http://tillageradish.com/
We grew a whole field of radishes and turnips last fall. (That field is in alfalfa this fall.) Our sheep grazed there in November and December. They ate so many they were burping radishes. They also got a little fat on them.
If you grow a big radish or other cover crop this fall, send a photo to firstname.lastname@example.org