Lack of sunlight will do this.

EJ in NJ

Billy wrote:
In article ,
"Ray" wrote:

Radishes are supposed to be so easy and quick to grow that Fourth Grade
students use them as science projects.

But in that field, I flunk. For years I've planted radish seeds -- in every
place, in every kind of soil, deep and shallow, but no matter what, they
always come up, form a spindly stem, and that's it. I never get a root.

What's the problem?

Hopefully, it is hard soil. This year I have very soft soil and I'm
hoping for a better crop of radishes. Shouldn't be long before I find
out. The other possibility is too much nitrogen which favors vegetaive
growth instead of root growth. Try steamed bone meal (1-13-0), and some
greensand or wood ashes, to stimulate root growth.