A close relative of the onion, garlic is an edible, bulbous plant native to Asia that has been cultivated for several thousand years. It is more popular today than ever and with good reason—it is packed with flavor and, for the novice home gardener, it is easy to grow, making it the ideal introduction to edible crops. It's almost impossible to not score a bountiful harvest on your first go at it, as long as you maintain the proper (minimal) conditions it requires.
Above ground, garlic appears as flattened, grass-like leaves (also known as scapes). In contrast, below ground, it forms a firm bulb, typically containing between four and 20 cloves, encased in a papery exterior. Garlic should be planted in the fall, about a month or so before the first frost. It will grow slowly over the next nine months and will deliver a bountiful harvest by mid-spring.
|Botanical Name||Allium sativum|
|Mature Size||12 to 18 in. tall, 6 to 12 in. wide|
|Sun Exposure||Full sun|
|Soil Type||Moist, well-drained|
|Soil pH||Slightly acidic to neutral (6.0 to 7.0)|
|Flower Color||Pink, white|
|Hardiness Zones||4 to 9 (USDA)|
|Toxicity||Toxic to dogs and cats|
How to Plant Garlic
When selecting a site for planting garlic, make sure it has not had onions or other alliums growing there in the previous season, and, ideally, not for at least three years.
It is a popular companion plant because it deters many pests and contains a naturally occurring fungicide that can help prevent diseases. Many other vegetables can be grown alongside garlic, including tomatoes, peppers, potatoes, carrots, and spinach. Planting garlic beside chamomile is said to help improve the flavor of the bulbs, and yarrow and summer savory could contribute to better growth. However, garlic and other alliums can stunt the growth of some plants, including beans, peas, sage, parsley and asparagus.
How Deep to Plant Garlic
You'll want holes that are around 3 inches deep in order to plant your garlic. Separate each hole by about 6 inches, and once planted, cover the your garlic with a layer of mulch—about 3 inches in height above ground. You should see garlic scapes emerge in about six to eight weeks.
While it may be surprising for a plant that grows primarily underground, garlic loves light. To ensure the best chance at growing success, plant your garlic in a spot that receives full sunlight for at least six to eight hours a day.
One of the most important factors in successfully growing garlic is to start with nutrient-rich soil. It should also be moist but well-draining, with an ideal pH of 6.0 to 7.0. It helps to add a layer of mulch atop your soil after planting to safeguard the bulbs, conserve moisture, and prevent the growth of weeds.
True to its easy-going nature, garlic doesn't have a ton of water requirements. It generally likes its soil moist and should receive around an inch of water per week, with a slight increase if the weather is especially warm. Keep the soil evenly moist throughout the first part of the growing season, but allow the soil to go dry for two or three weeks before harvesting—if conditions are too wet near harvest time, mold can grow.
Temperature and Humidity
Garlic is a very hardy plant, and it actually grows best through the colder winter months. That being said, be sure to plant your garlic seed about a month before the first hard frost in fall. Additionally, garlic has no special humidity requirements; it is often already harvested before the peak of summer heat and humidity.
The use of fertilizer can be beneficial when growing garlic. Mix a slow-release organic fertilizer blend into your soil as you plant your garlic in the fall. Then, when the leaves begin to grow in the spring, feed the soil surrounding your plantings with a fertilizer blend high in nitrogen.
The many sub-varieties of garlic fall into two basic categories: hardneck and softneck. Softneck varieties are best grown in warm climates, while hardneck is the garlic of choice for northern growers. Softneck garlic stores and travels better than hardneck garlic, and it has a stronger flavor and generally produces larger cloves. If you want a milder garlic taste, try elephant garlic—it's actually more closely related to leeks than it is to true garlic.
Hardneck garlic is so named for its stiff central stalk, or neck. It typically produces fewer cloves compared to softneck bulbs. The cloves tend to be all one size, forming a circle around the plant's neck. Popular varieties include:
- Rocambole: Has very thin skin that peels easily, but bulbs don't store as long as other types. Also called serpent garlic, due to its curling scapes, this is one of the most widely grown varieties
- Purple striped garlic: Includes several striped varieties with flavors ranging from mild to pungent; Starbright is prized for it's nutty flavor and storage quality, and Chesnok is good for roasting
- Porcelain garlic: Bulbs have only a few large cloves and thick skin that helps them store well. Georgian crystal is a mild variety, and Romanian red is spicy hot and tangy
Softneck garlic transports and store well and is the type most commonly sold at supermarkets.
- Artichoke: Commonly grown commercially. It is identifiable by its two concentric rows of cloves (and its resistance to peeling). Red Toch has cloves striped with red and pink and a balanced flavor
- Silverskin: Named for its silvery white skin, the bulbs have numerous small cloves and a sturdy neck that is good for braiding. Most types have a stronger flavor than artichoke types. Two bold and full-flavored varieties are Nootka Rose and Rose du Var
You'll know it's time to harvest your garlic when the majority of the bottom leaves have turned brown; this usually happens by mid to late summer. Dig up a test bulb or two to determine maturity—the garlic should be well-wrapped but not split.
To harvest, push a garden fork straight down into the soil about 6 to 8 inches away from the plant. Angle the fork so that it goes under the bulb and lifts it out of the ground. Don’t pull the bulb out by its leaves, or you risk breaking the bulb off. Use caution because garlic bruises easily.
Brush off any soil clinging to the bulbs. Allow the bulbs to cure or dry for three to four weeks in either a well-ventilated room or a dry, shady spot outside. Once the tops and roots have dried, they can be cut off. You can also further clean the bulbs by removing the outer skins. Just be careful not to expose any of the cloves.
Many garlic growers recommend cutting off the scapes, or topsets, of the garlic plants as soon as they start to curl, to conserve energy for the bulbs. Others prefer to leave the scapes intact because they feel it helps the bulbs in storage. Some take a middle-ground approach and cut off the scapes before they turn woody, when they are still good for cooking.
Garlic likes to be stored in cool temperatures, as low as 32 degrees Fahrenheit. The softneck varieties may last up to eight months. Hardneck varieties may dry out, sprout or go soft within two to four months. Keeping hardnecks at 32 degrees Fahrenheit sometimes helps them survive for up to seven months without deteriorating.
If you're a beginning seed saver, there is nothing easier than saving garlic. Simply put aside a few top-quality bulbs to plant next season. Store bulbs for replanting at room temperature, with fairly high humidity of about 70 percent.
How to Grow Garlic From Seed
Garlic is planted either in the fall or the spring, depending on your climate. In the north, plant garlic in the fall. It is best to plant garlic in early spring in warmer climates, though seed garlic must be chilled first to break it out of its dormant state.
When planting in fall, start as soon as the soil temperature has dropped to 60 degrees Fahrenheit. If you wait too long, the roots will not be able to prevent the plants from heaving upward when the soil freezes. You can help to prevent heaving by covering the plants with 3 to 4 inches of straw mulch.
To plant, start by separating the garlic bulbs into individual cloves, leaving the papery layer around each clove intact. Choose the largest cloves for planting and use the smaller ones for cooking or preserving. Plant the cloves 2 inches deep, placing each clove into its planting hole with the pointy tip facing up and the basal/root end facing down.
Space the cloves 4 to 6 inches apart in rows spaced about 2 inches apart. If you're tight on space, you can plant the cloves and rows closer together, but know that your bulbs will inevitably be smaller. Fill the planting hole with soil and pat it down gently. Top with mulch and water lightly.
Common Pests and Diseases
While a fairly hardy crop, garlic does have to contend with a few pests and diseases throughout its lifespan. White rot fungus, which typically develops in the middle of the season, is among the most serious diseases garlic can face. It infects the plants, turning the leaves yellow and causing them to wilt and die back. As the roots rot, infected plants can uproot easily. Be sure you obtain cloves from certified disease-free stock because once a field has been infected with white-rot fungus, it can take decades for the infection to completely clear.
Nematodes are another chronic problem for garlic. These microscopic worm-like creatures live inside the garlic plant itself, eating it while reproducing. Nematodes don't need water to survive and can live in the surrounding soil for several years. A nematode infestation can build up for several seasons without much damage and then strike and take out an entire crop. To control nematodes, make an effort to plant clean stock, inspect growing plants frequently, and remove any plants that look diseased.
Onion thrips have also been known to plague garlic. Thrips have rasping-sucking mouth parts that first damage the leaves then suck up the seeping plant fluid. Severe damage can cause the garlic plant to wilt and die. To control thrips, keep areas free of moist, wet mulch that provides breeding areas, and trap the insects with sticky traps.
Dilbo C. Integrated management of garli c white rot (Sclerotium cepivorum Berk)using some fungicides and antifungal trichoderma species. J Plant Pathol Microbiol. 2015;06(01).
Testen, A L., Walsh, E K., Taylor, C G., Miller, S A., Lopez-Nicora, H D. First Report of Bloat Nematode (Ditylenchus dipsaci) Infecting Garlic in Ohio. Plant Disease, 98,6,859, 2014, doi:10.1094/PDIS-11-13-1121-PDN
Gill, Harsimran K., Garg, Harsh, Gill, Arshdeep K., Gillett-Kaufman, Jennifer L., Nault, BA. Onion Thrips (Thysanoptera: Thripidae) Biology, Ecology, and Management in Onion Production Systems. Journal of Integrated Pest Management, 6,1, 2015, doi:10.1093/jipm/pmv006