Ok that sounds right - I may have pressed the oats button and then the barley one (which obviously did nothing).
Some visual feedback could help here - like showing an icon somwhere showing what you are about to plant.
Or make the little highlight on the button (took me a while before I noticed that) stand out more - could be much bigger and in yellow maybe.
If its any help, the crop grew into stalks which I couldn't walk through.