How to Grow Garlic
There's no reason not to plant this indispensable ingredient.
Download Planting Instructions
for Hardneck Garlic
"The majority of the world’s garlic is grown in China and is sprayed with chemicals and bleached white with chlorine during importation quarantine processes. Not to mention the thousands of food miles clocked up travelling long distances in storage. The presence of multiple pathogens in lots of seed garlic from six states and mainland China suggests that common pathogens of garlic are frequently transmitted within and between countries by germplasm sale and exchange (USDA).
Garlic grows in many regions around the world, including temperate regions, subtropical and tropical regions. Garlic is typically grown by planting an individual garlic clove. Cloves are separted from a garlic bulb. One clove, given the right conditions, will produce a garlic bulb or head containing many cloves, so it is a productive plant for sure! The garlic plant sends up a elongated, cylinder-shaped, solid, smooth stem, which can grow up 3 feet tall. The leaves, which are flattish, narrow, and about fifteen centimeters long, emerge from the bottom of the plant. Garlic plants have narrow, skinny leaves and they need all the sun they can get, and they need as little competition as possible from weeds.
Garlic, a Plant Description
The name "garlic" comes from garleac, an old Anglo-Saxon word meaning "spear leek." Garlic is believed to be descended from Allium longicuspis, a wild strain of Asian garlic but its origins are still in question. Garlic, and other members of the Alliaceae (Previously Amaryllidaceae) are native to central Asia and derive their characteristic flavor from the enzyme alliinase that acts on Sulphur compounds. All plants in this family are herbaceous, cool-season, biennial vegetables that are grown as annuals. Root systems are fibrous. Bulbs form from enlarged leaf bases called scales. Cold temperatures, combined with day length and soil temperature triggers bulb formation. Garlic (Allium sativum) is a cool-season hardy perennial made up of multiple cloves. Each clove is made up of one papery leaf and a second, thickened storage leaf which makes up most of the clove. Garlic leaves are solid, folded and flattened. This bulbous plant, grows vertical to an approximate height of 3 feet (1 meter). Garlic scapes can extend the height of this plant. Garlic rarely produces a hermaphrodite flower. The name Chicago is derived from the local Indian word chicagoua for the native garlic plant (not onion) Allium tricoccum.
Science has provided garlic growers and garlic connoisseurs, definitive information about the confusing subject of garlic groups and varieties. In 2003, Dr. Joachim Keller of the Institute the Leibniz Institute for Plant Genetics and Crop Plant Research in Gatersleben Germany, and Dr. Gayle Volk of the USDA in Colorado, used science to perform DNA analyses of garlics. They classified garlic into ten distinct groups including:
Five hardneck varieties called Porcelain, Purple Stripe, Marbled Purple Stripe, Glazed Purple Stripe, and Rocambole.
Three varieties of "weakly bolting" hardnecks that can produce softnecks - Creole, Asiatic and Turban.
Two distinct softneck varieties; Artichoke and Silverskin.
Garlic plants require full sun and grow best in loose soils with at least organic matter. Garlic tends to grow poorly in heavy clay soils. Alliums are shallow rooted and are sensitive to waterlogged conditions. Select a site that has full sun, well-drained soil with good moisture-holding capacity, minimum rocks along with a soil pH around 7. The soil should be free of weeds before planting.
Test your Soil
Perform a soil test early on; This is an analysis of a soil sample to determine nutrient content, composition, and other characteristics such as the acidity or pH level. Getting a soil test can help take the guesswork out of fixing nutrient issues. There’s no need to spend money on fertilizers that aren’t necessary. Garlic normally needs extra nitrogen (blood meal is a good organic source of nitrogen). Be sure to test your soil's pH. pH: Between 6.0 and 7.5 is the ideal pH for growing garlic. How do we increase the pH? Pick a liming material. If you have tested your soil and found that it is too acidic, you can raise the pH by adding a base. The most common materials used to increase the pH of soil are compounds made from powdered limestone, or lime. How do we decrease pH in soil? One of the best ways to increase acidity in soil is to add sulfur. Adding 1 to 3 ounces of ground rock sulfur per 1 square yard of soil will lower pH levels.
Alliums root systems are relatively shallow and seem to grow well in fluffy, loose, well-prepared soil. The soil should feel crumbly and loose. It should be free from most stones and rocks. Soils that are absent of organic matter should be amended with organic matter. Work rich, dark compost or well-rotted manure into the soil. The soil should be a minimum of 6-12 inches deep. If planting garlic in rows, keep an aisle on either side of the row to accommodate foot traffic and prevent the delicate roots from being compacted. If planting in raised beds, design the beds so you can plant, weed and access the garlic without having to reach too far.
Selecting Seed for Planting
For the most part, garlic is reproduced and grown from cloves. Garlic seed propagation depends mainly on the variety used and the climate where it is grown.
Hardneck varieties often produce flower stalks and are usually well adapted to cooler climates. Hardneck garlic has a slightly shorter shelf life, from five to seven months, while softneck varieties can be stored for up to nine months. Softneck garlic normally does not produce flower stalks; however, climate can be a factor as to whether or not this actually happens. Although some types of softneck garlic are suitable for cool climates, most do better in warmer environments. Your best chance for garlic seed propagation to be successful is to grow several varieties. Hardneck garlic is categorized into Hardneck Subtypes. There are three main subtypes of hardneck garlic, including Porcelain, Purple Stripe, Marbled Purple Stripe, Glazed Purple Stripe and Rocambole. In addition to the Hardneck Group, there are two other groups including Weakly Bolting Hardneck and Softneck.
Planting or replanting garlic from your own stock? Select the medium-sized or biggest and best cloves. If purchasing garlic seed, look for garlic sold specifically for planting. Supermarket-sold garlic may have been treated with a sprout inhibitor to prevent it from growing. Even worse, garlic imported from China may have been bleached and may also contain pathogens or mold. If you live in a warm climate such as California, growing softneck garlic may be the best option. If you live in a climate with cold winters and warm summers, consider growing hardneck garlic. Hardneck garlic produce a stiff stem that grows up through the center of the bulb. The stiff stem is made up of many individual leaf bases that resemble the growth rings of a tree. Compared to softneck varieties, they tend to have a sharper flavor, with more variation in flavor among the varieties. They're hardier too, making them a good choice for regions with very cold winters. Once harvested, the bulbs have a somewhat shorter shelf life than softneck varieties. Hardneck garlic tolerates cold winters and hot summers, so it's a fantastic plant for gardens in Montana, Idaho, Wyoming, Colorado, Washington, Oregon, North Dakota, South Dakota, Massachusetts, Minnesota, Connecticut, New England, Washington D.C., Maryland, Wisconsin, Michigan, New York, Maine, New Hampshire, Pennsylvania, New Jersey, Rhode Island, Virginia, Indiana, Illinois and Ohio. Gardeners and farmers that live below 40 degrees North Latitude also have had good success in growing garlic. Here are a few recommended cultivars: Chesnok Red, German Extra Hardy, Killarney Red, Spanish Roja, Music, Metechi, Rosewood, Georgian Crystal, Persian Star, Georgian Fire, Bogatyr.
When determining crop yields, keep in mind that every clove from a hardneck variety produces a single plant with (approximately) 4-6 new cloves. These yields assume good growing conditions. Your yield will depend on growing conditions, garlic variety, how much you weed, clove size and soil condition. In particular, poor draining soil will stunt garlic size. "Fluffy" soil offers less resistance to the growing bulb and cloves. If you plant a garlic variety that is unsuitable for your region, and you let weeds run rampant, it is probable you will have a poor crop. New growers may want to hedge their bets and plant more garlic.
Acclimatization is the process in which an individual garlic cloves copes and adjusts to the change in its environment. The factors of the environment include altitude, soil conditions, latitude, longitude, and an adjustment period. Acclimatization can take two or three years. Allow the individual garlic plants to remain adjust their performance across a range of environmental conditions.
How Much Garlic Should I Buy?
Purchasing 1-5 pounds of seed garlic will yield enough garlic for the culinary needs of most families. Your seed will reproduce and yield between 4-10 times the amount that you plant. This quantitative number varies greatly between varieties. As an example, planting one pound of Music garlic may produce 5 pounds in return.
When to Plant Garlic?
Plant garlic in fall about 6-8 weeks before the ground freezes. This allows the individual cloves to grow roots and become established before winter. These roots hold the garlic in place (like an anchor) and help prevent the bulb from being pushed up due to frost heaves.
Inspecting your Garlic Cloves Before Planting
Some of us are passionate about our garlic. We plant cloves in the fall and they magically grown into a beautiful plant in the following spring. However, several diseases can plague our garlic plants and the precious soil they grow in. Garlic is subject to several diseases that result in reduced yields, and in extreme cases, complete loss of the crop. Garlic is prone to several diseases. These include, but are not limited to: White Rot (Sclerotium cepivorum), Basal Rot (Fusarium culmorum), Botrytis Rot (Botrytis porri), Downy Mildew (Peronospora destructor), and Penicillium Decay (Penicillium hirsutum) which is also known as “blue mold”. Before planting, inspect the garlic (seed) cloves to determine if they are infected.
Soaking Garlic Before Planting?
Before putting the cloves into the ground, we soak them in two "stinky" solutions that provides two important benefits. If you’ve never done this before and have grown beautiful garlic, that is great news! I offer this suggestion to you, and ask that you be open minded to this garden tip, as it can prevent a tragedy in your garlic patch, and, it has the potential to help you grow even more exceptional garlic!
Garlic Soaking 101.
Soaking garlic provides two important benefits. First, soaking garlic in a solution of water, organic fish fertilizer and/or liquid seaweed fertilizer, and baking soda, for 24 hours, infuses the garlic with a boost of essential nutrients for growing in the spring. It like a fertilizer marinade, for the benefit of the garlic. The garlic will store this added energy and nutrients until spring. Second, we follow up with a short bath of vodka, rubbing alcohol or hydrogen peroxide, which will sterilize the cloves and destroy any mold, bacteria or other bad things that could survive the long, cold winter, and play mischief and create chaos in your garlic patch, next spring. This short, second soak, acts as an antiseptic, capable of destroying tiny mites hiding in the cloves, fungal diseases and microbes (or at least prevent or inhibit their growth). It doesn't get the garlic drunk.
First Soaking : 8-24 Hours.
This first soak is pretty simple. Our ingredient list is baking soda, water, and fish emulsion (and/or liquid seaweed fertilizer).
Fish emulsion fertilizer is made from whole fish and carcass products, including heads, eyes, bones, scales and skin. This product is processed to remove oils, and the liquid that remains after processing is fish emulsion. After straining out solids, sulfuric acid is added to lower the pH, preventing microbes from growing. A common fish emulsion is: Alaska Fish Fertilizer 5-1-1 . Liquid seaweed fertilizer is an alternative to fish emulsion. Liquid seaweed fertilizer is a concentrated formula containing nitrogen and nutrients. Most seaweed-based fertilizers are made from kelp, a variety of seaweed that can grow to lengths of over 40 metres. Trace elements found in organic seaweed fertilizers include magnesium, potassium, zinc, iron and nitrogen—all of which are beneficial to garlic. Nitrogen, for instance, is essential to the production of nitrate, a key component needed by plants during photosynthesis.
Let's Begin by mixing the ingredients into a large stainless steel bowl or container.
1 gallon of lukewarm water.
1 Tablespoon of organic fish fertilizer (and/or 1 additional Tablespoon of liquid seaweed).
1 Tablespoon of baking soda.
Baking soda—otherwise known as sodium bicarbonate diminishes the pH gradient across bacterial membranes. The antibacterial activity of baking soda has been shown to kill bacterial suspensions when baking soda was combined with the detergent sodium dodecylsulfate. (National Institute of Health).
We then gently place the cloves into the container, keeping all the garlic labels near each variety for easy identification. We let the cloves soak for 8 to 24 hours. You'll notice at the end of this stinky bath, some of the cloves may have increased in size do to the infusion and added fluid volume in the garlic's interstitial and intravascular space. Some of the garlic may be floating at the surface, others may be on the bottom of the container. Drain the fluid using a colander.
Second Soaking - Quick!
Our second soak goes quickly. We place the garlic cloves into a stainless steel container and cover with either Vodka, Isopropyl Alcohol 70%, or Hydrogen Peroxide. Soak for 10 minutes and drain.
Special Note: isopropyl alcohol is stinky and inhaling moderate amounts of isopropyl alcohol can cause irritation of the nose and mucous membranes, throat irritations, nausea, vomiting, and even difficulty with breathing. Perform this second soak in a well-ventilated area!
Just prior to planting, we let the cloves drain for a few minutes - this process ensures all the liquid is removed. We also wash our hands with soap before handling the garlic cloves as an added measure. Plant within 1 hour of the second soak.
How to Plant Garlic?
Garlic is propagated vegetatively, by planting cloves saved from the previous crop. In other words, garlic grows from individual cloves broken off from a whole bulb. Each clove will multiply in the ground, forming a new bulb that consists of many cloves.
Prior to putting the cloves in the ground, break up the garlic heads to gain access to the individual cloves, leaving as much of the papery covering on each clove intact as possible. Select only the firmest, largest cloves to plant. Put the smaller cloves aside for now, and use them for cooking or baking. Discard cloves with bruises or those that are soft. These cloves are potential targets for fungal organisms in the soil. Handle the cloves gently. Don't let them fall onto a hard surface as the “basal plate”, or base, of the clove may become damaged. The basil plate is the underlying stem of the future garlic plant. Any damage to the plate can result in a smaller garlic head or clove rot.
Plant cloves 2-3 inches deep, orienting them so the pointy ends face up. Plant cloves 4, 5 or 6 inches apart. Garlic is commonly planted in double or triple rows that are 2-3 feet apart. If planting in rows, leave plenty of space around each plant - enough space to walk or navigate any equipment you may use to weed, water and harvest. This helps prevent the soil around the growing bulb from getting compacted. Growing garlic from bulbils or seed is also a possibility. Some growers believe that growing garlic from garlic 'seeds' (which are small bulbs that develop at the tip of the garlic scape) can help the garlic adapt to your climate. Growing from bulbils may produce more robust garlic over time.
To Mulch or not to Mulch?
If tender shoots begin to grow in the late fall, mulch the plants with a layer of 4-6 inches of weed-free straw. Ideally, shred the straw (not hay) and lay down this protective mulch over the garlic. In cold-winter regions the mulch should be approximately 4 inches thick. Why add mulch over the garlic? Three reasons. First: Mulch will help to prevent the garlic roots from being heaved out of the ground by alternate freezing and thawing. Second: The straw adds nutrients to the soil and, over time, helps keep the soil "fluffy" as the straw breaks down and becomes integrated into the soil. Third: An application of mulch is useful to "snuff out" and control the growth of weeds.
What to Expect in the Spring
Roots will continue to grow in the spring and sprouts will emerge from the single clove. Green sprouts will metamorphose into a shoot and will continue growing in earnest as the snow melts and the soil temperature increases. To encourage good growth, add a small amount of high-nitrogen fertilizer that decomposes slowly, around each plant. Examples of such fertilizer include blood meal, fish meal, chicken manure (aged), horse manure (aged), and bat guano (aged). Gently work the nitrogen into the soil near each plant. During the spring and summer, keep the area around the garlic weeded. In late spring or early summer, hardneck garlic varieties produce a flower on a coiled scape. The flower stalks are made up of small bulbils. Unless you plan to start a new crop of garlic from bulbils/seed, plan to cut these curly stalks off (also known as garlic scapes). This will insure that energy the plant produces will go into the garlic bulb and not the clusters of bulbils. Eventually, the garlic plants stop producing new leaves and begin to form bulbs underground.
Pests and Diseases
Garlic has few problems with pests in the garden. Deer stay clear from this plant. Some gardeners consider garlic a natural pest repellent. Thought, growing garlic is not fool-proof. Even though garlic has very few problems with the diseases that plague other veggies, keep an eye out for white rot. White Rot is a fungus that may attack garlic in cool weather. Not much can be done to control or prevent that problem except rotating your crops and cleaning up the area after harvesting. The spores can live in the soil for many years. The fungus affects the base of the leaves and roots.
Garlic is susceptible to other diseases including (but are not limited to) : Basal Rot (Fusarium culmorum), White Rot (Sclerotium cepivorum), Downy Mildew (Peronospora destructor), Botrytis Rot (Botrytis porri) and Penicillium Decay (Penicillium hirsutum). Most of the major garlic diseases are soilborn, so proper site assessment and yearly rotations are crucial in maintaining a healthy garden of garlic. In addition to these diseases, garlic is also subject to damage by several genera of nematodes. Avoid planting infected sets; rotate crops to non-allium species for 3-4 years; plant in well-draining areas and do not overcrowd plants; destroy all infected crop.
Good prevention from diseases include:
1. Annual rotation of garlic crops.
2. Planting only healthy and vigorous garlic cloves.
3. Roguing (culling) diseased- or stunted-looking plants as soon as symptoms appear.
4. Try not to leave garlic plant debris in the field: collect all refuse and put it into the garbage or even better burn it. Do not compost garlic debris.
5. Rotate crops using a cover cropping: In particular, clover and mustard is an natural biofumigant that has been proven effective against nematodes, and helps build soil organic matter.
White rot is the most significant disease affecting allium production worldwide, and has resurfaced in the New York garlic industry after a long period of eradication. Careful management can reduce inoculum, and because the pathogen is spread by seed and soil, it is also possible to prevent its spread into uninfested fields. White Rot is caused by Sclerotium cepivorum, an ascomycete fungus which is related to white mold fungi (Sclerotinia family). The pathogen is spread through mycelia and sclerotia movement in the soil and on seed garlic, but not as airborne spores. Only 1 sclerotium per 10 liters of soil is enough to cause disease, and 10-20 sclerotia will cause upwards of 90% infestation. Generally these levels of sclerotia in the soil can be reached in 2-4 cropping cycles of alliums grown under favorable conditions (Crowe, 1980). One of the primary reasons this disease is of critical concern is that once sclerotia are in the soil, they can remain viable for up to 40 years (Schwartz and Mohan, 2008). White rot sclerotia will remain dormant in the soil until a suitable host (an allium) is detected through sulfur compounds secreted by the plant. Soil temperature is the greatest factor contributing to the speed of disease movement; at 48° F germination is very slow; optimum at 57- 64°F, and terminates at 70°F (Schwartz and Mohan, 2008). Ideal moisture levels for disease development are the same as for crop growth. White rot damage is generally detected first as yellowing or wilting of the foliage just prior to scape emergence, though the infestation started much earlier. The above ground symptoms can correspond with underground symptoms including degradation of the roots and basal plate, formation of black sclerotia the size of poppy seeds, and briefly a white mycelial mat on the bulb extending up to the soil line. (source: Cornell University).
Garlic competes awfully with weeds, and weed pressure can decrease garlic yields by 10-40 percent. Formulate your weed-control plan before planting; This should include crop rotations, analysis of soil fertility, and reduction of weed seeds (through tilling).
Remove the Garlic Scape
Hardneck garlic produces a scape; A tube-like structure that curls onto itself. At the tip of the scape, a flower-like structure is created known as a bulbils. These garlic scapes protrude upwards and are firm, round flower stems. We recommend removing the scape. Why? Scapes are delicious and can be used just like garlic. Most importantly, by removing the scape, the garlic bulbs (and individual cloves) will be larger, as compared to a plant that was allowed to keep its scape. In other words, removing the scape from the garlic plant will deter the plant from sinking energy into the bulbils and instead divert the energy into the cloves. The garlic plant has a finite amount of energy.
When and How to Harvest
In northern climates, harvest times (from the previous fall plantings) will range from late June to August. Around this time, stop watering. The garlic will store better if you allow the soil around the bulbs to dry out. Supplement with nitrogen after planting and a few times during the growing season. The clue is to look for yellowing foliage. Harvest when the bottom 3-4 leaves are yellow and drooping, but before they are completely dry. Before digging up your whole crop, sample a few bulbs first. Dig a bulb to see if the crop is ready. If pulled too early, the bulb wrapping will be thin and may disintegrate. Ideally, the plump cloves that make up the garlic head, will be covered with the white papery, garlic skin. If you can see the individual bulbs protruding from the head, you've waited too long to harvest, and the bulbs have split apart. If left in the ground too long, the exposed bulbs are more susceptible to disease and may not store long. To harvest, carefully dig the bulbs from the soil using a spade, garden fork or shovel. Lift the plants, carefully brush off the soil, and let them cure in a shady, dry spot for at least two weeks (depending on your local humidity). Lay the plants on a mesh material, allowing air to circulate around the plant, or hang bunches on a string. Make sure all sides get good air circulation. Be careful not to bruise the garlic or it won’t store well.
After the garlic has cured, it is time to clean the garlic. Handle garlic heads gently because they bruise easily. After the garlic has dried and cured, any soil or dirt will brush off fairly easily. Gently brush off the excess dirt, but leave the outer skin layers intact. A paint brush with stiff fibers can facilitate cleaning the heads. Using a heavy-duty clipper or PVC / tube cutter, trim the stalk to one (1) or two (2) inches and trim the roots to a quarter inch in length.
The History of (Eating) Growing Garlic
The Egyptians wrote about growing garlic for thousands years ago. Garlic and Onion have been identified in drawings on Egyptian tombs dating back to 2800 B.C. Onions and garlic have been used as medicine, food, and as an aphrodisiac. Apparently, the builders of the pyramids lived mostly on onions and garlic. The laborers who built King Tut's tomb were so dependent on the bulb that they went on strike when their garlic rations were decreased. Garlic, hung over doors and near an entryway to a home was thought to have had powers to ward off evil spirits. Garlic provided strength and courage to Greek athletes and warriors. It was believed that juices from this pungent plant, when rubbed on entry doors and door frames, kept out blood-thirsty vampires. Garlic is known universally as "the stinking rose". This phrase or term reportedly goes way back to Greek and Roman times. The "stinking" part is obvious, but why "rose"? Garlic is an allium which is part of the Liliaceae family. Garlic is closer to a lily than a rose. So what is the origin of the name? Unfortunately there is no clear answer to this question. How about genghis khan? Did he grow garlic?
For humans, the health benefits of garlic have been touted for centuries. Today, researchers may have pinpointed at least one reason why. A new study shows red blood cells process compounds from digested garlic and turn them into the cell messenger hydrogen sulfide (H2S), which relaxes blood vessels and increases blood flow. Therefore, eating garlic may increase our natural supply of this vital chemical and play a role in reducing the risk of heart disease. Previous studies on garlic’s health effects have produced mixed results. For example, some studies of garlic have found few benefits, but others have been shown to lower the risk of heart disease. (Source: WebMD.com)
Garlic (Allium sativum L.), like other plants, has an exquisite defense system, composed of as many different components as the human immune system. In order to protect itself from insects and fungi, garlic produces allicin by enzymatic reaction when it is injured. Thus, allicin is mother-nature’s insecticide. Since ancient times, garlic has been used worldwide, not only as a food, but also as a medicine. As early as 3000 B.C., in ancient civilizations, including Egyptian, Phoenicians, Greek, Indian, Roman, Babylonian, Viking, and Chinese, garlic was used for treatment of heart conditions, arthritis, pulmonary complaints, abdominal growths (particularly uterine), respiratory infections, skin disease, symptoms of aging, diarrhea, headache, bites, worms, wounds, ulcers, and tumors. The ancient Chinese consumed garlic to achieve longevity. In the days of the Pharaohns, during the building of Great Pyramid of Cheops at Gizeh, when the supplies of garlic ran out the work force withdrew their labor. They knew well that garlic gave them strength and stamina. In the first century AD, Dioscorides, the chief physician of Roman army, prescribed garlic to his warriors and wrote: garlic cleans the arteries. The use of garlic to treat wounds surfaced repeatedly through the middle ages into
World War II, when garlic was used to treat the wounds of soldiers. (Source: Mohammad Shafiur Rahman. Taylor and Francis. Allicin and Other Functional Active Components in Garlic).
Garlic may have health benefits for humans, but don't feed your four-legged pet garlic. Toxic doses of garlic can cause damage to the red blood cells (making them more likely to rupture) leading to anemia. Signs of garlic poisoning can be delayed and not apparent for several days. While tiny amounts of these foods in some pets, especially dogs, may be safe, large amounts can be very toxic.
Additional Resources on Growing Garlic
Montana State University (MSU) Bozeman
Ohio State University Extension
Oregon State University (OSU) Extension
Utah State University Extension
Iowa State University Extension and Outreach
Penn State University Extension
University of Maryland Extension
University of Maryland Extension