Crop Stunting With Potions

I want a way to make crops to stop growing by throwing a poison potion on them.

I want this done so that there is more options for building. And also to make farming crops harder. If a witch were to spawn near your farm, it may trample your crops or if you engage in combat with it, and it throws a poison splash potion. Your field is now stunted and you need to fix it. Giving more of a reason to protect your farms. And also giving more dynamic choices in how the player wants to secure a food source.