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What to know about growing garlic

Garlic, a member of the onion family, should be planted in late September or October so it will be well rooted by November.
Garlic, a member of the onion family, should be planted in late September or October so it will be well rooted by November. Centre Daily Times, file

My colleague Elsa Sanchez and I were recently visiting Jim Crawford at New Morning Farm, a certified organic farm located in southern Huntingdon County, and had the opportunity to observe a nice crop of garlic hanging in the barn. That led me to think about all the culinary and health benefits of using garlic. And we happen to be approaching the perfect time to plant garlic.

Garlic (Allium sativum) is a species in the onion family that includes onion, shallot, leek and chive. It should be planted in late September or October so it will be well rooted by November. Garlic should be planted at least 4 inches apart in rows 16 to 18 inches apart. Plant it vertically 1 to 2 inches deep. Growth will resume in the spring, and the crop will mature in August. While plant survival with spring plantings may be greater, the growing period before bulbing may be too short for satisfactory yields.

Garlic is propagated by planting cloves, which are the small bulblets or segments making up the whole garlic bulb. A large garlic bulb will contain about 10 cloves and all cloves can be planted except those that weigh less than 1 gram, and those that have any side growth. The cloves, or young growing plants, must be exposed to cold temperatures between 32 and 50 degrees for one or two months to initiate bulbing. With fall plantings, the cold treatment is accomplished quite naturally throughout the winter.

When the tops become partly dry and bend to the ground, garlic is usually ready to harvest. The bulbs are pulled and can be cured (thoroughly dried) in a well-ventilated shed or garage.

After curing, diseased and damaged bulbs should be discarded. The remaining bulbs should be cleaned to remove the outer loose portions of the sheath and the roots should be trimmed off close to the bulb. The bulbs may be braided or bunched together by their tops, or the tops and roots may be cut off and bulbs bagged like dry onions.

Garlic is best stored under the temperature and humidity conditions required for onions (32 to 60 degrees and 70 percent relative humidity). Garlic gloves will sprout quickly after bulbs have been stored at temperatures near 40 degrees, so prolonged storage in this range should be avoided. Garlic stored at humidities more than 70 percent at any temperature will not only mold but will begin to develop roots.

Garlic is divided into two broad categories: hardneck and softneck. In the case of softneck garlic, these varieties are better keepers that can be stored for longer periods of time while maintaining their quality. Softneck garlic varieties also have flexible stems or stalks that allow these garlics to be used to create fancy garlic braids and wreaths.

Hardneck garlic varieties are better known for their wide range of delicious flavors and the gourmet qualities that they exhibit in the kitchen. They produce larger cloves that are easier to separate and peel, making them popular with gourmet chefs. Hardneck varieties don’t keep in storage quite as long, will produce edible garlic scapes during summer, and are not suitable for braiding or creating garlic wreaths.

Bill Lamont is a professor and extension vegetable specialist in the department of plant science at Penn State and can be reached by email at wlamont@psu.edu.