Green Thumb – Growing Garlic

Posted: September 20, 2022

Want to get a head start on planting your vegetable garden for next year? Then garlic is the plant for you!

Garlic (Allium sativum) has been grown for thousands of years as both food and medicine. It has a long growing season which may seem daunting. Fortunately, it is relatively easy to grow and has relatively few pest problems.

In order to properly produce, garlic requires a cold period, therefore it should be planted six to eight weeks before the ground is expected to freeze. This is usually late September to early October. This will give the cloves time to produce roots and to begin growing shoots before the ground freezes, as well as provide them with their chilling requirement during the winter. Come spring, they will resume their growth.

There are two main types of garlic: softneck and hardneck. Hardneck garlic produces a hard stalk called a scape, which is where the name hardneck comes from. It is easy to peel and is more winter hardy, but it has a shorter storage life. On the other hand softneck garlic stores well, which is why we typically find it in grocery stores, but it does not peel as easily. Softneck garlic rarely produces a flower stalk, thus the softneck name.

Garlic should be planted in well-drained soil in full sun. It does best in soils with an abundance of organic matter. Therefore, make sure to amend soils with compost or well-rotted organic matter. In addition to adding organic matter, apply two to three pounds of 10-10-10 fertilizer per 100 square feet before planting.

It is best to get your garlic from garden centers or catalogs. Garlic sold in grocery stores is usually treated to prevent it from sprouting, so it’s not a good choice for planting.

Once you have your garlic bulbs they should be broken apart into individual cloves, but don’t do it until right before planting. Choose the largest cloves for planting to get the best yields. Cloves that are diseased or soft should be discarded and small or damaged ones can be used in the kitchen. Once the soil has been prepared and you have selected your cloves, plant them one to two inches deep and four to five inches apart with 15 to 18 inches between rows. Make sure to plant the cloves with the pointed side facing up.

Garlic is related to onions and is susceptible to the same pests and diseases such as thrips, onion maggots, and bulb rots. Because of this, try to avoid planting garlic in areas where you have recently grown onions.

Garlic is a poor competitor, making weed control important if you want to get good yields. A four-to-six-inch layer of weed-free straw or other organic mulch can be added to help control weeds as well as help moderate soil temperatures.

During the growing season try to keep the soil evenly moist. If the soil gets too dry it can result in small irregularly shaped bulbs. (They need about an inch of water a week). If you’re growing a hardneck variety remove the scapes as they appear. This will allow the plant to commit its energy to developing the bulb instead of the flower.

Garlic should be harvested when half of the leaves have turned yellow (usually around July, depending on the weather). Bulbs should be cured in a cool, dry, well-ventilated area for several weeks. Once your garlic is cured, the stems and roots can be cut off and bulbs cleaned by removing the outer-most skin. Just make sure not to expose the cloves. Finally, they should be stored in a cool, dry, dark place.

Ken Johnson is a Horticulture Educator serving Calhoun, Cass, Greene, Morgan and Scott counties. He is one of the authors of the “Good Growing blog” at go.illinois.edu/goodgrowing. The Green Thumb page is coordinated by DeKalb County Master Gardener Janice Weber.

Got a Gardening Question?
Send your questions to the Master Gardener Help Desk at uiemg-dekalb@illinois.edu.

Photos courtesy of Ken Johnson & David Pusti

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