There should be a new area that you can buy from wood and stone called "The Farm". In this area, you can plant and harvest plants that vary on different levels,i.e. potatoes on level 1 and carrots on level 2. These plants can be planted using a certain type of hoe by right clicking on tilled soil spaces. They can grow after a certain amount of time and then harvested. Once harvested they can be sold at the warehouse for gold, but are not used in buildings.