Are you in story or sandbox? I think I figured out what the issue is. There are 4 stages for the Farm story/unlock. It unlocks at 4, but I cannot recall exactly what that last phase is (I believe it has something to do with Sebastian, maybe 1 remaining quest?). I adjusted it so it'll unlock on 3 so it'll appear when you first get the farm (it'll change in version 0.9.3)