Like in one farm it can capacitate 12 vills like a tc can garisson, even a farm can garrison, not exactly like aoe3 but instead like we cant see 12 vills moving around on farm and more like a tc with 12 vills garrisoned. And the 3*4 grid farm must farm only one grid for one vill garissoned and rest grids must be barren until the no. of vills keep increasing in the farm.