May I just ask for more details -how- exactly this is happening? You're seemingly the only person on the server to even mention possible griefing.
There's quite a few buildings and structures around the spawn and somehow your place is the only one to, allegedly, have been griefed. It just seems a bit odd to me, especially since you just complain about griefing without going into detail what has happened.
Considering you live in a village, have you considered that the villagers might have done something? Villagers usually harvest grown plants. Also, have you considered the simple solution of putting a sign on your house and/or around the village to indicate that it's not a random village/house but actually belongs to you?