Hi Mike,

This fall I am planning on using one of my raised beds (8" x 4' x 32') for garlic. While New Hampshire is not as cold as you undoubtedly encounter (we have weeks of single digits, but it is rare for similar extended periods sub-zero) I am confident it will work for me. I am considering mulching the sides of the raised beds as well as the tops, and you should certainly do so in Alaska. If you were to add an additional 14" - 18" of mulch a foot or two out against the sides of the raised beds you should be set. Of course you should still have 6" - 10" of mulch above the bed.

I guess it comes down to how deep your frost line gets (snow is an excellent insulator); you should be able to protect your raised bed with mulch so that it fares no worse that an in ground garlic plot. In general, I would encourage you to try it; I think you odds are good, and the rewards are great.

Update- z2-3 Anchorage

Both the in-ground and the raised 18" tall wood-frame beds did just fine for overwintering, we had lots of garlic! Most or all plants of all varieties survived under 6-10" straw and leaf mulch. Took a long time to thaw in spring, the beds appeared frozen through, and plants seemed none the worse.

Siberian was by far best performer with consistently largest bulbs, and they are keeping much better than other varieties too. Small downside is that cloves are "sticky" when cutting open compared to other varieties.

Music, my second favorite of the bunch, was very pretty and very tasty but all bulbs were small. Spanish roja stood out for flavor, but size was variable by plant, shriveled quickly in storage. Other varieties - including chesenok red, korean red, bogatyr, killarney red were unremarkable, small and stored poorly.

Thanks for all the advice. It's been much, much colder this winter so we'll see how the garlic fares this time out.