When is the best time to plant garlic?
Answer: Fall/early winter planting is recommended in all parts of the U.S. A cold period is required in order for the mother bulb to split into cloves. The bolting cultivars of garlic require a cold period to trigger cellular division. For spring planting, which is not recommended, the bulbs need to be refrigerated at 40°F for 40 days. By planting garlic in the fall, the plants obtain significant root growth before the ground freezes. Then in the spring the plant focuses its energy on sprouting, leaf growth, and ultimately bulb development. If the garlic is planted too late in the fall to obtain significant root growth, this will ultimately detract from bulb size the following summer. Fall-planted garlic grows rapidly when the weather warms in spring.
Bulb growth in garlic, like many alliums, is dependent on the lengthening of the day and the accumulation of degree days (heat units). In northern latitudes, most growers plant garlic in October before the ground freezes. This gives the plant time to make good root development but not enough time to make leaf growth. Where winter sets in earlier, growers are recommended to plant garlic two to three weeks after the first frost (below 32°F). Where winters are milder, garlic can be planted as late as mid-December. In some parts of California, it can be planted as late as February or March. ATTRA recommends talking with local producers and your county Cooperative Extension to determine the best time to plant garlic in your region.
You can learn much more in the ATTRA publication Garlic: Organic Production. This publication addresses most aspects of organic garlic production, including seed sources, organic fertility management, pest management and harvesting and storage. Marketing and economic considerations, including enterprise budgets for organic garlic production, are also addressed.