Getting more of specific item to harvest

Find whatever you are shortest on (for me, it's corn) and put one of those at the farthest point top-and-left. The animal and the plant at the top left are the two that visitors will harvest. Get them ready-to-harvest, and when a visitor harvests them? YOU get a freebie of that type, too. The corn I put at the top has given me plenty of it as visitors come :)