Some of my Kohlrabi didn't bulb, but grew long and skinny. What causes that to happen?
Certified GKH Gardening Expert
This can happen for a few reasons. The first is that they were not planted deep enough. Another reason can be that they were stressed, especially if they were stressed as seedlings. They have a harder time forming a bulb. Too little light can keep them from forming a proper bulb and too little nutrients as well.