Why do garlic pots have holes?
Actually, it isn't really to allow the garlic to dry, it's the opposite (to help prevent it from drying out too much).


  Most models of the garlic pot are relatively small and usually round. Often, the garlic pot is constructed of some sort of porous material, such as fired ceramics or terra cotta. Both types of the garlic pot will feature a lid that is loose fitting, allowing for quick retrieval of the garlic clove from the container. In addition, the garlic pot will have a series of air holes on the backside of the body of the container. These holes supply the garlic bulb with proper circulation and help to prevent the garlic from drying out. Coupled with the lid, the garlic pot also protects the garlic from direct contact with light, which could hasten the process of mould appearing on the garlic.


http://www.wisegeek.com/what-is-a-garlic-pot.htm


  A garlic keeper is a small garlic pot which is designed to stay cool and which has holes to allow air to circulate  


http://www.garlic-central.com/keeper.html