Something I discovered quite by accident while farming my Oasis house (the yard has 50 available item slots) ... I used a Plant All spell on a group of 12 medium plots but I didn't check the available remaining space on my property before I did it... I was already at 46/50. It worked, and populated all of the open plots with the seed I had selected but in doing so the item/space indicator jumped up to 58/50 so I had effectively exceeded the maximum capacity of the property. I panicked and ran around and picked up some random items to reduce it to 50/50 so I don't know what would have happened if I'd left it alone... I was planting Couch Potatoes and didn't want to run the risk of losing any of them but I'm going to try it again with some seeds I don't care about losing just to see what will happen.