No rocks. I'm in that area of MN with really awesome/fertile black dirt, relatively flat land, and very few rocks. Rain just depends on the year. Sometimes we'll be great other times not. July/August are usually the worst with lack of rain, otherwise we're pretty good.
Farmer friend said his disk is too big, so I'll have to look into other options. It would be really great if I could get the ok to find a little sand to mix in.