I've been trying to setup my current family in their house for the better part of the afternoon.
Tried to place the grow stations, one placed just fine and other wouldn't. It gave me the message of can't place on slope. I was able to level out using the Level Terrain tool.
I did try to flatten the lot before placing the house, but that doesn't seem to help. Somehow the lot the house sits on got uneven. It most likely happened when I moved it before saving it.