The Harvest Barn comes with the special set bonus. The amount of resources earned per day depends on the buildings age and to how many other Harvest Garden Set buildings it is adjacent to. Additionally, the number of neighbooring set pieces that provide a bonus to the Harvest Barn depend on the level of the Harvest Barn and is three for the lowest level and six for the highest level.
The Harvest Barn can be motivated, doubling its coin output. It requires a road connection.
The Harvest Barn can be upgraded by Harvest Barn Upgrade Kit item. To upgrade the Harvest Barn, use the Harvest Barn Upgrade item on the Harvest Barn that is already situated in your city. Its upgraded version will then be placed directly on the same spot in your city and the production timer will not be reset. Note that the upgraded building will be from your current era, even if the old one was from one of the earlier ages.
As the Harvest Barn does not produce special resources upon motivation, it has a low priority in the motivation order and will only get motivated randomly with the regular buildings after all special buildings that produce forge points, goods, guild power, medals, or blue prints have been motivated. Use a Self-Aid Kit if you want to make sure your Harvest Barn is protected from plunderers if you cannot collect on time and you have regular plunderers coming along.
Every 24 hours the Harvest Barn will produce the following resources. Base resources will always be produced. Bonus resources are determined by how many other unique Harvest Farm Set buildings it is connected to.