Take good notice of this as well:
At some point of time, the greens will stop growing. When they dry up and turn brown, dig out the cloves and each of them should have formed a full bulb. Take a clove from that bulb and start all over.
When to plant garlic
In fall, plant cloves in well-drained beds after the first frost has passed and the soil is cool. Cloves can also be planted in late winter as soon as the soil thaws, but fall-planted garlic produces bigger, better bulbs.
Garlic likes a lot of moisture, but will start to develop yellow leaves if they stay wet for too long. Since garlic loves cold weather, experimenters from zones 9-11 might be better off choosing another variety through mail order. On the bright side, you can also grow elephant garlic using the same instructions and it typically performs much better in warmer climates than its smaller cousin.