How do you see if a tile was watered?
With no tools or objects in your hands, click on the crop (as if you were to water it). It'll tell you the stage it's at.
I haven't got the game at this point in time but if i remember correctly that should work, i remember dealing with this myself at one point and either this was the answer or it was just simply that in this version there is absolutely know way of knowing without making a physical note of it.