Garlic has been cultivated since ancient times. Today it is used as a condiment and as flavoring in gravies, tomato sauces, soups, stews, pickles, salads, salad dressings, and breads.
Garlic (Allium sativum) is a member of the onion family. Other edible members of the onion family include chives, leeks, and shallots.
While garlic and onions are similar, there are differences. Garlic has flat leaves rather than the round, hollow leaves of the onion. Garlic produces a number of small bulbs called cloves rather than one large bulb. Each garlic bulb contains several cloves enclosed in a white or purplish parchment-like sheath or skin.
There are several types or forms of garlic cultivated in the home garden. "Top-setting" varieties form bulbils or bulblets at the terminal end of a hollow seedstalk. The bulbils are initially enclosed in a globe-shaped structure. The outer sheath eventually splits, exposing the cluster of small, pea-size bulblets.
Elephant or greatheaded garlic (Allium ampeloprasum) is not a true garlic. It is actually more closely related to the leek. Elephant garlic does produce segmented bulbs similar to garlic. However, elephant garlic has a much milder garlic favor and may be 3 to 4 times the size of true garlic.
Rocambole or serpent garlic produces flower stalks that are distinctly twisted or coiled, sometimes even double-coiled.
Garlic grows best in well-drained, fertile soils that are high in organic matter. Garlic grown in heavy, clay soils often produces misshapened bulbs. Heavy, clay soils can be improved by incorporating organic matter, such as compost or well-rotted manure. Garlic also requires full sun.
Since garlic rarely produces seed, it is grown by planting cloves. Garlic cloves can be planted in the fall or as soon as the ground can be worked in the spring (late March to early April in central Iowa). Highest yields are obtained from the largest cloves.
Carefully break apart the garlic cloves immediately before planting. Place cloves 3 to 5 inches apart within the row. Rows should be spaced 18 to 24 inches apart. Set the cloves 1/2 to 1 inch deep.
Fall planted garlic should be mulched with several inches of straw to help prevent winter injury. Apply the mulch in late fall and promptly remove in early spring.
Top-setting garlic varieties can also be grown from the bulbils or bulblets that form at the top of the seedstalk. The bulblets should be planted in early spring where they can remain for 1 1/2 years. The bulblets will form larger, unsegmented bulbs called "rounds" by the end of the growing season. Left undisturbed in the ground, they will form a cluster of cloves by the end of the following summer.
Garlic has a high fertilizer requirement. Apply and incorporate 1 to 2 pounds of an all purpose garden fertilizer, such as 10-10-10, per 100 square feet of garden area prior to planting. Lightly incorporate one additional pound per 100 foot row of the all-purpose garden fertilizer in a band 4 inches to the side of the developing plants 3 to4 weeks after plants emerge in the spring.
Garlic requires 1 inch of water each week. Irrigate garlic once a week during dry weather. Stop irrigating in late July to allow the foliage to die down prior to harvest.
Garlic has a shallow root system. Control weeds with shallow cultivation or by applying a mulch between rows.
Harvest garlic when the foliage begins to dry. In Iowa, garlic is usually harvested in August or September. Carefully dig the bulbs with a garden fork or shovel. Dry the garlic in a warm, well-ventilated location. Place the garlic on an elevated wire screen or slotted tray to promote drying. When the tops have dried, cut off the dry foliage 1 inch above the bulbs. Also, trim off the roots and brush off any loose soil. Place the bulbs in a mesh bag and store in a cool (32 F), dry (65 to 70% relative humidity) area. Properly cured and stored garlic should keep for 6 to 7 months.
An alternate way to store garlic is to braid the foliage together immediately after harvest, dry, then hang the braided garlic in a cool, dry location.
An occasional problem encountered by gardeners is the production of unsegmented bulbs or "rounds." This may be the result of planting cloves that are too small, planting in late spring, or poor growing conditions during the growing season.
This article originally appeared in the February 28, 1997 issue, p. 15.