It is not necessary to cover it. Here in NC we often have our garlic that high all winter with temps in the teens!
The garlic lady

agree with Garlic Lady, the garlic will be just fine.

Hey, thanks Garlic Lady and username_5. That's good news. This stuff just takes care of itself!

However, I've noticed bed preparation is the most important thing. I have two beds right next to each other. One bed I had dug down about 15" and put in half composted straw, horse manure and grass clippings. The other I put in nothing. That was last year and of course the uncomposted bed showed much smaller plants. What is interesting is that last fall I dug up both beds equally and added a considerable amount of composted cow manure. The plants this year are healthy in both beds, but the original compost bed shows significantly larger plants. All that straw and stuff is still making a difference! I was shocked. So next time I dig a new bed, I'm going all out. It pays off for more than one year. Just some advice for any newbies who might be reading this. Oh, and it more than makes up for clove size. I had cloves that were much smaller in the compost bed end up giving me much bigger bulbs than the big cloves planted in the uncomposted bed. Ya gotta love it.