Wow, I don't know. This is my first year growing garlic (and other alliums for that matter).
I know last spring I had just returned from Iraq and was living at my in-laws home. We had some garlic that had sprouted in April so I put about 6 cloves out in the ground out back. Two months later they were huge (at least above ground). I found work and moved aobut 2 hours away. On my next visit I found that my in-laws had gotten rid of them assuming they were weeds, so I don't know.
This year however, I do have a bunch of garlic planted (back in late October). Got about 8 varieties along with 2 shallots and a multiplier onion. We'll see how it works this time.