Filmed During A Drought
Field of Dreams was filmed in Iowa during the middle of a drought, which required the baseball field and iconic cornfields in the area to be heavily watered during the production.
As a result, the crops grew at such a fast rate that it actually outgrew several of the shots. In at least one scene in the movie Kevin Costner is walking on an elevated plank through the corn to account for the difference in height from the previous shot.
Speaking of Kevin Costner—he nearly missed out on the career defining role of Ray Kinsella. The part was initially offered to Tom Hanks, who turned it down. Not that Hanks wouldn't have been good in the movie, but Costner needed it more.