Board Thread:Questions and Answers/@comment-94.213.150.180-20130603143810/@comment-198.82.80.191-20140603061912

I was having the same problem, check to see if your nether wart has an EMC value. If it doesnt have an EMC value(I.E: wont grow on crops and dirt) then it wont work for cross breeding. I'm currently waiting on mine to reach stage three now