Although it is generally recommended that garlic be stored at 0oC , research by Volk et al suggests that -3oC is actually better for both soft and hard-neck types of garlic. Storage at -3oC resulted in superior flavor and color, slowed sprouting and reduced decay relative to storage at 0oC or warmer. Low temperature storage also improved the yield potential and quality when the garlic was planted out the next spring.
Source : Volk, Rotinoo and Lyons (2006). HortScience 39:571-573.