Bulb growth in garlic depends on the warmth and the length of the day. In northern parts of the United States, most growers plant garlic in October before the ground freezes. This gives the garlic plant time to develop good roots but not enough time to encourage leaf growth before cooler weather hits. Where winters are milder, like here in Central Texas, garlic can be planted as late as mid-December.
Planting garlic yourself is easy. Crack each garlic bulb into individual cloves -- that's called "popping" the bulb. Plant the cloves with the root end down about one inch deep.