I’ve been counting kohlrabi the same as cabbage. I'm not sure if that’s right or wrong. I was going to ask my COD on how to count it but most likely they’ll just say “It’s not in the book so you can’t have it”.
Yes, green turnips are in the book and they're counted the same way as cabbage. I mentioned cabbage because the "kohl" in "kohlrabi" means cabbage in German and we use kohlrabi a lot like cabbage in my German community!