This is my second year trying to grow French Breakfast radishes. I've tried them in containers, sandy soil, loamy soil, compact soil, windowbox, overwatered, underwatered, etc. They always sprout up quickly- they get their true leaves 5 days after I sow them! But, for all my efforts, I've produced one radish and by the time it was big enough to eat it was cracked and woody. What am I doing wrong! Or better yet, what's the recipe of thinning/sun/water/soil which will produce nice plump radishes in the supposed 25 days it says on the seed packet. Should I try a different variety? Any help would be great.

-Ross