Farming is a method of producing money. It is currently the only known way to make money within your own base. Nomads do not have a farm.
Before you farm, your king must purchase a farm for 5000 dollars.
To farm, you use a 'harvest' tool which the player has once he/she spawns. Repeatedly click the wheat until it collapses and you will receive 20-40 dollars. In the general store, you can purchase a better hoe for 2000 dollars. If you disconnect while you have a better hoe, you will lose it. The better hoe harvests wheat much faster.