Growing Garlic

By Cindy Haynes
Extension Horticulturalist
​Iowa State University

With Halloween just around the corner, children of all ages are beginning to conjure images of ghouls and goblins. As a horticulturist, I naturally think of plants associated with the upcoming holiday. Pumpkins immediately come to mind. Garlic is another. Legend says that garlic helps keep the vampires away -- which is always a good reason to have plenty of garlic around at Halloween. Besides fending off vampires, there are other good reasons to have garlic in the house. Garlic is great in sauces, stews, dressings, spreads, soups and other dishes. It is also good for you.

Garlic (Allium sativum) is relatively easy to grow in the home garden. It is a member of the onion family along with leeks, chives and shallots. Each garlic bulb contains a dozen or more smaller bulbs, called cloves. The cloves are enclosed by a white or purplish, dry, parchment-like skin.

There are generally two types of garlic grown in home gardens: hardneck and softneck types. Hardneck types usually produce a flower stalk and softneck types do not. The flowers on hardneck types sometimes abort and produce small bulbs (called bulbils) instead. These are called “topsetting” garlic varieties. Softneck types produce pliable stems (or necks) that can be braided after harvest, hence the name softneck. The foliage of hardneck types are generally too stiff to be braided. The garlic sold at grocery stores or supermarkets are primarily softneck types that are commonly grown in California or overseas.

In Iowa, it is usually easiest to grow the hardneck types. They tolerate our cooler weather better than some softneck types. Within the hardneck type of garlic there are many options including: rocambole, purple stripe, glazed purple stripe, marbled purple stripe, porcelain and Asiatic varieties. These are available through mail-order companies or Internet sites, and some local garden centers. Don’t purchase bulbs from the grocery store for planting outdoors. Bulbs sold in grocery stores may have been sprayed to prevent sprouting -- which allows them to keep longer indoors, but limits the number of cloves that will emerge after planting.

Elephant garlic (Allium ampeloprasum) is not a true garlic. It is actually more closely related to leeks than garlic. Elephant garlic differs from true garlic in bulb size and flavor. Elephant garlic has a milder flavor and may be 3 to 4 times the size of true garlic. 
Believe it or not, fall is the best time to plant garlic In Iowa. All types of garlic prefer sunny sites with fertile, well-drained soils. Soils enriched with plenty of organic matter are preferred. Heavy clay soils often produce misshapened bulbs.

Prior to planting, gently break apart the garlic cloves. The largest, often outer, cloves are the most productive. Instead of planting the smallest cloves, store them in the refrigerator for use in cooking. Plant the cloves one inch deep with the pointed side up. Place cloves three to five inches apart in rows. Rows should be spaced 18 to 24 inches apart. After planting, place several inches of straw on top of the rows to help insulate and protect the cloves over the winter. Promptly remove the straw in early spring.

Garlic is considered a “heavy feeder”. To maximize crop yields, apply and incorporate one pound of a complete fertilizer (such as 10-10-10) per 100 square feet of garden area prior to planting. Next spring, apply one additional pound of the all-purpose garden fertilizer per 100-foot row about three to four weeks after the shoots emerge. Lightly sprinkle the fertilizer in a band next to the plants.

Garlic requires one inch of water per week in spring. Irrigate weekly during dry weather. Since garlic is a poor competitor with weeds, frequent weeding also will be needed during the growing season.

Harvest garlic when the foliage starts to turn brown. In Iowa, garlic is usually ready to harvest in August. Carefully dig up the bulbs and allow them to dry for several days in a warm, dark, well-ventilated location. When the bulbs are dry, you can remove dry foliage, roots and any remaining soil. For best keeping quality, bulbs should be stored at 32-40 F and 60-70 percent relative humidity. Your refrigerator is an ideal place to store garlic. Properly cured and stored garlic should keep for six months or more.

A successful gardening year should reward you with plenty of garlic to use in soups, stews and other dishes. There should also be enough to scare away those pesky, blood-sucking vampires on Halloween.

Cindy Haynes, Horticulture, (515) 294-4006,