The knowledge of plant farming allows the character to raise crops. The character will know the proper time of season to plant seeds, when to harvest, how to irrigate. Additionally, the farmer will know what pests and vermin the crops are vulnerable to. While the farming skill requires Perception in the planning stages, the actual act of farming requires Endurance. Thus, once the crops are planned, (Perception), they must then be planted and subsequently harvested (Endurance.) Farmers also have keen knowledge of proper prices for farm goods (it is thus much harder for them to be ripped off by merchants selling such goods) and because of their knowledge, they can usually get a 10% reduction in the price on farm products by going to the best merchants assuming that there are multiple merchants in town.
Critical Success: The crops will yield 1d10x10% more than expected.
Critical Failure: The crops will yield only 1d6x10% of normal density.