Garlic is sensitive to heat and excess sunlight so leaving garlic in the ground until all the leaves have died down allows potentially hot weather to start "cooking" the bulbs. The more leaves that die the more likely you are to have some of the outer bulb wrappers split which lets dirt, moisture and disease organisms in to the bulb. Garlic has an aggressive root system that makes pulling them difficult if not impossible. Use a shovel or preferably a potato/digging fork to lift the bulbs out of the ground. Carefully knock the loose dirt off the roots. Don t leave in the bulbs in direct sunlight for very long (more than fifteen minutes.) Tie up to ten plants together with twine and hang in a dry and warm location to dry out. Tying more than about ten plants together can result in longer drying periods and more chance for storage molds to start developing. You want the tops to finish drying down so there is no moisture left in the neck when you cut it. Depending on the year and location this may take two to six weeks. Once the necks are dry, trim the tops back to about one inch.
"Hard-necked" cultivars will require pruning clippers to do this, "soft-necked" cultivars can be trimmed with heavy scissors. Brush the remaining dirt out of the roots and trim them back to about a quarter of an inch. If outer bulb wrappers are dirty carefully remove them but don’t remove any more than necessary. Bulb wrappers help protect the cloves.
Carefully check each bulb for soundness by gently squeezing the bulb to check firmness. If any bulbs seem excessively soft, set them apart to be used first. Like onions they are best stored in mesh bags and should never be stored in sealed plastic bags. Paper sacks can be used but pack them lightly. Ideal storage conditions are 32 to 35 degrees and 65 to 70% humidity. For most gardeners you are better to just leave them at cool room temperature. Refrigerator storage conditions very closely replicate fall soil conditions when planting and will stimulate cloves to start bud swelling and germinating. Not all garlic types have the same storage life. Some will only store for 4 to 6 months, while others can store for 10 to 12 months. (Chuck Otte)