URBANA, Ill. - Garlic is a long-season, over-wintering crop that does best when planted in the fall. It can then be harvested in the early summer, which allows space for another crop.
“This is rather unusual timing in the gardening world and it has always interested me for that reason,” says University of Illinois horticulture educator Ryan Pankau. “Planting garlic is a great way to end the gardening season by caching away a crop for early harvest next year.”
In Illinois, fall planting of garlic is best, although spring planting is possible. In fall, plant early enough so the bulb has time to root and grow prior to the first hard freeze (28 degrees Fahrenheit or below), which is typically sometime in October. It is generally recommended to plant about two to six weeks prior to a hard freeze.
“I have planted a little later (into November) with ample success,” Pankau explains. “This can sometimes be a balancing act as planting should be timed to allow root development and limited top growth prior to a hard freeze, but not so early that too much tender top growth occurs and is killed back by winter, wasting energy stores.”
Garlic requires cold treatment for optimal shoot and bulb formation; therefore, spring-planted garlic must be stored in the refrigerator for approximately eight weeks to meet chill requirements. Spring plantings must be put in the ground as soon as soils are workable to allow enough time for bulb development prior to hot weather. Fall soil preparation is recommended for spring plantings.
“Fall-planted garlic will obtain its cold requirements in the soil and has the advantage of additional root growth prior to freezing temperatures, affording it a head start in spring,” he says. “For this reason, fall planting is the recommended method in Illinois.”
Seed can be acquired from local growers or from online sources. Store-bought garlic is not recommended for planting as it is typically treated to prevent sprouting. Each garlic bulb contains up to about a dozen individual cloves. Separate the bulbs into cloves shortly before planting. Research has shown that early separation into cloves and storage prior to planting will lead to less yield, so always store garlic as an entire bulb. It is recommended that you remove the papery outer covering on the clove, similar to preparing it for cooking, prior to planting.
“However, I have had success with and without observing this step, based on the time available for peeling garlic,” Pankau adds. “Peeling and prepping the cloves is actually a great task to do the night before planting, saving you time on planting day.”
Begin planting by creating a furrow approximately one to two inches deep. Individual cloves should be planted three to five inches apart in an upright position (pointed end up) to ensure a straight neck or stem. Cover the cloves with one to two inches of soil. Each row should be 18-30 inches apart or you may plant five inches apart in all directions to create a stand of garlic with no rows.
Garlic prefers well-drained soils with high fertility. “To accomplish this, I have always used raised beds with significant amounts of compost added to the soil,” he explains.
Similar to onion, garlic is highly sensitive to weed competition. The beauty of fall planting is that weed competition will be relatively low until next spring and summer. Mulch is great way to reduce weeds and should be applied at planting time in the fall.
“In my home garden, garlic has been one of our most successful crops,” Pankau says. Home gardeners can easily save seed for next year if storage conditions are optimal.
“Over successive seasons, by selecting the biggest and best bulbs to save, you can develop your own ‘variety’ that is specially adapted to your local climate,” Pankau concludes.