Break the cloves off of the garlic head and plant in full-sun in well-drained soil. Plant the hard and softneck types 1-2 inches deep. Then, in the spring, side-dress with compost or blood meal.
When 75% of the leaves are brown, the garlic is ready to pick. Lay plants in airy, dark, dry spot for several weeks to cure. Save the largest, healthiest bulbs to for next year.
Garlic is said to help repel aphids.
History (via Wikipedia):
Garlic has been used as both food and medicine in many cultures for thousands of years, dating at least as far back as the time that the Giza pyramids were built. Garlic is still grown in Egypt, but the Syrian variety is the kind most esteemed now.
Garlic is mentioned in the Bible and the Talmud. Hippocrates, Galen, Pliny the Elder, and Dioscorides all mention the use of garlic for many conditions, including parasites, respiratory problems, poor digestion, and low energy. Its use in China was first mentioned in A.D. 510.
Garlic was rare in traditional English cuisine (though it is said to have been grown in England before 1548) and has been a much more common ingredient in Mediterranean Europe. Garlic was placed by the ancient Greeks on the piles of stones at crossroads, as a supper for Hecate (Theophrastus, Characters, The Superstitious Man); and according to Pliny, garlic and onions were invoked as deities by the Egyptians at the taking of oaths. (Pliny also states that garlic demagnetizes lodestones, which is not factual.) The inhabitants of Pelusium, in lower Egypt (who worshiped the onion), are said to have had an aversion to both onions and garlic as food.