Strong farming urns can be used to gain additional Farming experience while training. When held in the inventory, urns are filled as the player farms. Only base experience counts towards filling the urn. Full urns can be teleported away to receive an additional 1,100 Farming experience. Only one urn is filled at a time, though players may own up to a total of 10 full urns. If a player owns 10 full farming urns they must teleport at least 1 away before they can fill more urns.
A strong farming urn requires level 58 Crafting to make. Crafting a strong farming urn (unf) on a potter's wheel gives 35xp, and firing it in a pottery oven grants 52.5xp.