First, check to see if they really vanished. Hover the mouse over the empty spot where the plot, crop, machine, animal, building and other items are supposed to be.
If you see any text message here, it means that the crop or item is not really vanished; it just became invisible.Invisible crops/items
Being invisible means that the item or crop is actually still there, and is still working. Only the graphic did not load, or did not load fast enough.
This is most likely caused by the (lack of) speed of your internet connection. The faster your internet connection, the least likely this problem will occur.
To prevent your crops or items from becoming invisible, turn off all running processes or programs on your computer that you don't need. Close all unnecessary windows and applications. Also, do not upload or download anything while playing.If your crops really vanished...
Then contact us. To see how, check this forum posting: http://familyfarm-forum.socialgamenet.com/viewtopic.php?f=13&t=193