Growing Garlic
Guest Blog by Matt Suhr of Happy Dirt Veggie Patch
Garlic has been cultivated since prehistoric times. The wild ancestors of the garlic that we know and use today grow in the harsh climate of the foothills of the mountains of Central Asia. The area stretching roughly from Iran in the west to extreme western China is dry and hot in the summer, and very cold and sometimes snowy in winter. Wild garlic is adapted to poor soils and extremes of temperature and moisture.
Garlic was likely nurtured in place by hunter/gatherer peoples, and gradually was domesticated into what we know as garlic today in two main types, hardneck and softneck. Modern garlic is bigger and easier to grow than wild garlic.
There are many varieties within each type, as well as related crops like “elephant garlic”, which is technically a leek with very mild flavor. Of the two types, softneck is what you will almost always find in grocery stores. Hardneck is more of a specialty available at farmers markets and natural food stores.
Garlic is a tough plant that can survive in harsh conditions, but if you want nice big bulbs that are easy to use you have to pamper them a bit. Garlic is slow, but it doesn't ask all that much of you as a gardener--just occasional faith and love and timely attention to some key details.
Distinguishing characteristics:
Hardneck-- fewer, larger cloves per bulb; has a stiff flower stalk which is edible when young (“scapes”); peels more easily; tends to have richer flavor; yields less; has shorter shelf life. More closely related to wild garlic, it requires cold winter temperatures to perform well.
Softneck-- More cloves per bulb, with more small inner cloves; often larger overall bulb size; pliable stalk which can be braided; more climate adaptability; higher yields; longer shelf life.
You need garlic to grow garlic. Wild garlic can sometimes produce viable seeds, but cultivated garlic has never been known to do so-- the flowers that form on the stalks are sterile. Garlic in the garden is propagated by dividing the bulb into single cloves and planting them individually. Also, little bulbils that form on the flower stalks can be planted, but take several years to grow into full size bulbs.
Since it has a limited shelf life, and there is no seed to be had, garlic must be planted each and every year in succession, from a saved portion of the previous season's crop. If you fail to produce a crop you must start anew. It's a commitment!
When you find a variety that works well for you, it is wise to keep it going year after year. Typically, garlic will increase each season by a factor of roughly 5 to 10X what was planted. You can gain higher yields if you are satisfied with bulbs full of many small cloves.
When properly stored, a crop that is harvested in summer will easily last until fall planting in good condition. See Storage later in this article.
Timing
Garlic, especially the softneck types, is adaptable to many climates and soil types. It grows best when planted in fall. There are several factors to consider to determine the optimal time in any specific area, but you will almost always do well to aim for the month of October. The idea is to plant before the ground freezes in winter, but not too early. Planting too early will produce larger bulbs, but they will have more issues like smaller/more numerous skinny cloves, double cloves, lighter weight bulbs for their size, and poor keeping quality. Planting too late does not allow adequate root growth before winter, and the plants get a late start on spring growth and overall size and yield is reduced. However, in hardneck types, late planting can improve flavor and keeping quality.
The further north you are, the earlier you can plant. In mild winter climates you can wait until late fall.
In general, softneck types are more tolerant of climatic conditions. They grow well planted almost anywhere in the continental U.S. Hardneck types only do well in places that have at least some freezing weather in winter. As long as the onset of freezing weather isn't too sudden, garlic is quite hardy and will survive very cold conditions. With a blanket of snow, or deep mulch, they can make it through almost any kind of cold.
So a good rule of thumb in most areas is to plant after the first frost, but before the ground freezes or significant snow happens. That's typically a window of several weeks--October in most of the mid-latitude US.
Site and Soil
Garlic prefers a sunny site and moderately fertile, balanced soil. Full sun is best. In hot climates some partial shade in the afternoons is good. In general, more hours of sun means more potential for large bulbs. If your site is shady part of the day it is still worth growing garlic, but your bulb size will be reduced. If your site is very shady, garlic will grow but not produce much worth harvesting. Any soil type can work to grow garlic, although heavy clay is challenging come harvest time. The ideal is a loamy mix of sand, silt and clay with mid-range pH, but really almost anything somewhat loose and well-drained (no standing puddles during wet weather) will work.
Garlic can usually make do with average levels of potassium and phosphorus, but additional nitrogen will boost the overall yield, especially if applied in early spring. See Growing on below for fertilizer advice.
Planting
Any healthy garlic bulb can be used for planting. Bulbs that are selected for large size, disease-free and true-to-type for planting purposes can be purchased at a premium price from many seed and plant dealers. This is a good way to get started with a known variety and fewer chances for problems. If you are on a tight budget, garlic sold for direct eating purposes also works fine in most cases. You will want to be more discerning about size, firmness and type. Reject any bulbs with missing or rotten cloves or any sign of mold. Traces of black mold on the outer skin are OK, but reject anything greenish, pinkish or whitish, or that causes softening/discoloration of the interior. Some diseases and pests are transmitted via the planted clove, and you don't want to contaminate an otherwise pristine garden with pathogens.
The potential final size of your crop of garlic depends on the size of the individual clove you plant, as well as the size of the entire bulb that clove came from. And, of course, the growing conditions through the growth cycle have a big effect as well.
The ideal planting bulb is firm and large-- but not necessarily huge. You want relatively few cloves so that each one is larger. For hardneck types, 2 to 2 1/2” diameter is optimal. For softneck types, you can go a smidge bigger up to 2 3/4”. Huge bulbs tend to have shorter shelf life and weaker flavor, so going for just plain large is your best bet. You can certainly plant the smaller bulbs, but the likelihood is that the harvest will be proportionately smaller as well.
As to which variety to plant-- it really comes down to a basic choice of softneck or hardneck, or both. Within those categories they all require similar conditions, so you should make your choice based on culinary or aesthetic preferences. If you like to live in the moment, or are lazy, you can just go with whatever is most readily available. To some people garlic is garlic and that's ok. If you are a connoisseur, you will want to choose wisely.
Once you have selected your planting bulbs, and planting time is nigh, you need to pop the individual cloves from the bulbs. It is important to be sure to separate all the cloves. Sometimes they are conjoined within a single wrapper. You can see if there are two cloves together by examining the basal plate. If two cloves are planted together, they will come out smaller and flattened on one side. Not the end of the world, but wouldn't you rather have nice symmetrical garlic? After popping, the metabolism speeds up and you want to plant the cloves promptly.
The shape of the clove makes no difference to the final bulb, but size does matter. Especially in softneck types, the skinny inner cloves often are not worth planting with the bigger ones. Good growing conditions will increase the size, but won't turn a tiny clove into a large bulb in a single season. However, small cloves as well as any bulbils can be planted close together in a separate area of the garden and used for green garlic. Green garlic is basically like a scallion, but garlic flavored. They are yummy, and can be harvested and enjoyed in the spring---long before the bulbs are ready--as a welcome foreshadowing of the bumper crop to come!
Plant the cloves pointy end up, flat end down. The growing shoot emerges from the pointed tip; roots swell and then emerge from the perimeter of the basal plate. The ideal in most situations is to cover the clove such that the pointed tip has about 1-2” of soil covering it. In very cold climates you can go deeper to insulate from extreme temperature swings. If you plant deeper than 4”, germination is slower and more variable, the plants are smaller and much harder to harvest. If you plant upside down, the roots and shoots will eventually find their way, but at the cost of growing time and beauty. The resulting bulbs will be smaller and misshapen.
There is a range of spacing options for each type, depending on how fertile your soil is, and how big you want your bulbs to get. The rule of thumb is to allow a minimum distance of twice the desired bulb diameter. So, in your mind's eye imagine the size of bulb you realistically want to produce—then leave at least twice that distance between each bulb. So if you want a 2 1/2” bulb, leave at least 5 inches between planted cloves.
If you are planting in a grid pattern, you're looking at 5-7” spacing in most situations. If you crowd them closer than that, they will grow ok but come out proportionately smaller. If planting a single row with room on each side, you can go down to 4” spacing in fertile soil. Softneck types can use slightly more room than hardnecks, as they ultimately average out to be larger bulbs.
If you have a favorite weeding tool or hoe, be sure the spacing you use allows the tool to fit between the plants. Your future self will thank you!
Growing on
After planting, if the soil is dry give it a good soak. Though garlic can survive dry conditions, if you want nice big bulbs you need to keep the soil moist and get the germination process going right away. Spread a thin mulch at planting time, and add to it when the shoots pop out of the ground and as needed thereafter. Your goal is to maintain good even soil moisture through winter and spring until harvest time approaches in early summer.
The first stage of growth is root emergence. After that, the green shoot starts growing. In mild conditions, garlic will show green sprouting leaves within about a month of planting. In cold conditions heading into winter there may be no visible growth until the temperatures start to increase again. Visible or not, root growth is taking place down below all winter long. Hardneck types benefit greatly from a winter chill that forces the plant to pause growth. Softnecks do fine in mild winter areas.
When the season shifts from winter to spring, garlic starts putting on green top growth. This is the time that most determines how big your harvest will be. It is a good time to fertilize. It is a good time to mulch with aged compost and water it well so the leached goodness feeds the microbes in the root zone. Any good natural fertilizer will help as long as it contains significant nitrogen. Rapid green growth requires nitrogen in the root zone. The bigger, thicker and greener the tops get, the bigger the bulbs will be.
Good sources of nitrogen include chicken manure, blood meal, feather meal, alfalfa meal and your very own pee (diluted 10:1). Anything with significant organic matter, like aged cow or horse manure, is also good. Avoid sawdust or other wood based materials as soil amendments. They take very long to decompose and tie up soil nitrogen in the process of decaying. Sawdust is OK as a mulch to discourage weeds and retain moisture, just don't dig it into the soil below. Aged compost is always good, both as an amendment and as a mulch.
Garlic has an affinity for sulfur and selenium in the soil. It is efficient at scavenging them, so unless you have a specific deficiency there is no need to supplement your soil with these minerals separately. Get a soil test to know where you stand, but usually it is not an issue as most any organic matter you add to your soil will contain adequate amounts.
If you don't have any compost handy, you would still do well to mulch with any organic matter you have lying around, such as dry grass clippings, leaves, straw animal bedding, etc. Mulch of any kind helps keep the soil temperature and moisture levels stable, which allows soil microbes to proliferate. Ultimately, it is these microbes that provide nourishment to the growing plant. Microbes need a steady supply of air, water, mild temperatures and food to thrive. Any organic material you add on top of the soil will eventually make its way to become microbe food.
Mulch also helps discourage weeds from germinating. Garlic does not like competition from weeds.
In dry climates, weeds that have not yet gone to seed can be used as mulch. Just pull them and lay them down around the plants. In a day or two they will be shriveled and create a little moist pocket underneath for soil microcritters to frolic in.
As a general rule, try to keep your garlic patch 100% weed free. Towards the end of the season as the bulbs are forming, garlic will be drawing fewer nutrients from the soil and you can get away with letting some small weeds start to creep in. Don't let it get overrun, though, or harvesting will be much more difficult.
Towards the end of the vegetative growing period, hardneck garlic provides a special treat: scapes. As the plant matures it sends up a flower stalk which forms a curlicue that soon straightens into an upright stalk, the scape. It is good to snap this off to force the plant to direct its energy to bulb development. Best to do this while it is curly. If you leave the scapes on, the bulbs will turn out significantly smaller. Scapes are delicious any way you might use garlic, though not quite as intense as the main harvest bulbs. If you wait too long to snap them off, they turn woody and not so palatable, and your yield diminishes.
Pests and Diseases
In many dry areas and isolated gardens, garlic is a relatively trouble-free crop. However, if you live in an area that is humid during the main growing season, or if you are in an area that has commercial production of Allium family crops, you will likely face some pest and disease issues at some point. Even if you start out with a trouble-free situation, you can easily introduce problems if you are not careful.
Most nibbly critters that roam your garden will avoid garlic. Exception: gophers and ground squirrels love garlic. There are various ways to discourage rodent damage, like burying hardware cloth below the crop. This works in raised beds, but becomes impractical in larger gardens and farms. There are various ways to eliminate or limit the populations of burrowing rodents, or move them along to new horizons. Smoke bombs; flooding tunnels; wind driven whirlygigs that vibrate the soil; feral cats; spring-loaded traps; castor oil; Juicy Fruit gum. None of them work 100% of the time, but usually at least one method will work if practiced diligently.
Other pests that can attack garlic include nematodes, onion thrips, onion maggots and wireworms.
Common Garlic Diseases
White Rot (Sclerotium cepivorum)– This fungus causes the leaves to die back and bulbs to turn to white fluffy mush. No cure is known, and it persists in soil for many years. Prevention is key. It is most active when temperatures are cool. Above 75° F it is inhibited, but it takes temps over 113° F to kill it. It is spread not by spores, but tiny black beads called sclerotia. These are found all over the infected bulb and surrounding soil. Best to avoid this entirely by starting with certified planting stock or being ever vigilant for rotting bulbs. In isolated cases, dispose of any you find, along with the surrounding soil, away from the garden. If your whole garden is infected there is not much to be done, and you will have a very difficult time growing garlic.
Basal Rot (Fusarium oxysporum)-This is very similar in effect to white rot, but occurs in warm weather and is a bit slower acting. It shows up as soft bulbs that separate from the basal plate at harvest or shriveled cloves during storage. Same preventive measures as for white rot.
Penicillium Molds (Penicillium corymbiferum)- Indicated by the typical blue-green color, this mold affects stored cloves, as well as young plants. It is spread by airborne spores in storage and while handling prior to planting. Reject any planting stock that shows mold. This mold stunts young plants, and often kills them. It doesn't spread very quickly in soil, fortunately. Wet conditions help to control it. Best is to avoid planting any infected cloves in the first place.
Viruses- A multitude of viruses infect garlic, but most of them have little effect on yield or quality. One virus that does affect yield to varying degrees is Yellow Dwarf virus. It is transmitted by thrips and aphids, and shows up as yellow streaks on younger leaves, eventually killing off that leaf. Depending on when in the season it hits and how resistant your strain of garlic is, the impact can be anything from very mild to severe. Not much can be done about it once you spot it. Prevention is iffy as well as it's hard to totally prevent thrips and aphids from doing their thing. Thankfully, this is not a common problem in garden scale plantings.
Common Garlic Pests
Nematodes- Stem and Bulb Nematode causes stunted, twisted plants with spongy rotten bottoms that break off from the basal plate when the plant is pulled. No cure is known, and they persist in soil for many years--so prevention is the key. Nematodes are usually too small to see, so you know them by the damage they cause. They are usually spread by planting infected cloves, or by planting in a space that previously grew alternate host crops, such as other onion family crops, Shasta peas, parsley, celery or salsify (a common weed). Be sure to use planting stock from a reputable source, and be on the lookout for any kind of rot on the cloves you plant. If you discover infected plants, dig them out and burn them or put them in the trash.
Thrips- Onion thrips are common in garlic patches, causing multitudes of tiny white or silvery spots and streaks. Both the adults and the larval form suck on plant juices, and can reduce or wipe out an entire crop, depending on severity. They thrive in warm and dry conditions. Their life cycle is very quick, around 2 to 3 weeks, so you can have multiple generations throughout the growing season. A foliar spray such as kelp—with 2-3% fish oil added will help control thrips. Safer® soap is also sometimes effective. Keeping a diversified patch of beneficial insect attractor flowers nearby will also help, as the larval stages of ladybugs and syrphid flies, among others, will eat the immature stages of thrips.
Wireworms- Wireworms are the larval stage of the Click Beetle. They bore little tunnels into the cloves making them unpalatable. They also attack other root vegetables like turnips, carrots and radishes. They typically congregate in fields that recently grew sod. If your garden is newly established from turf and has lots of wireworms, growing good garlic may be difficult. The solution is to do several non-host crop rotations, turning the soil between crops to dry it out and kill them off.
There is also a predatory nematode, Steinernema feltiae, that attacks wireworms. It works best as a preventative in warm conditions, well before you plant garlic. Once your crop is growing the nematodes will be less effective.
Harvest Time
When garlic slows leaf production and starts to form a bulb, harvest time is near. As soon as top growth slows--or in the case of hardneck types after the scape has been plucked-- you want to withhold watering. A little rain or random watering won't be too bad, but you want to encourage the plant to draw its energy inwards toward the bulb, and discourage any molds or pathogens that might affect the delicate wrappers.
It is important to harvest at the right time. Too early gets you smaller bulbs with reduced shelf life and shriveled wrappers. Too late gets you disintegrated bulbs with separated cloves and no wrappers. Getting it right gives you firm clean bulbs with bright, tight wrappers that are a pleasure to behold. Harvest time can be anywhere from May to September, depending on where you live and the variety of garlic you are growing. Other gardeners in your neighborhood will know when to expect garlic to come in, but ultimately you need to be able to read the signs your plants show to you.
Each leaf on the garlic plant connects to a wrapper layer. Fresh green leaves correlate to firm complete wrapper layers. Dry brown leaves correspond to wrapper layers that are in rapid decay. Wrapper layers that are decaying will be lost during the harvest, curing and cleaning process.
The ideal time to harvest is when about half the leaves are brown. Even better is to count and pick it when there are still at least five green leaves. This will allow the loss of a couple layers during processing and leave you with three beautiful wrapper layers in the final product. This will ensure a good shelf life and visual appeal.
If you are lucky and have very loose soil and strong tops, you can simply yank the plants out of the ground to harvest. More often, they will require some digging. A digging fork or small shovel, or a strong trowel can all be used to harvest. Place the tool far enough away from the garlic so there is no chance of stabbing or slicing it, then lever it under the plant to lift and loosen the soil enough to pull it from the top. The freshly dug bulbs are moist and bruise easily, so resist the temptation to toss them about. Especially keep the bulbs from knocking into each other.
Gently lay them out on the ground as you harvest. Rub off any clinging dirt clods. You can eat garlic fresh from the ground, but to make it shelf stable it requires a curing period after harvest to reduce the moisture level. It needs warm temperatures, good air circulation and no direct sun. Usually about two weeks hanging in bunches from the rafters of a shed or porch will do it. Or you could spread it out on a tarp in a garage or under a thick shady tree, as long as there is good air movement. In high humidity areas it could take longer. You are trying to avoid conditions that would lead to mold or sunburn. It is done when the tops and outer wrappers are completely crispy.
When your crop has finished curing it is time to trim and clean the bulbs. Actually, you can wait as long as you want to do this step. Garlic keeps just fine with the tops and roots connected. But why wait? Nice clean garlic on your kitchen counter brings good feelings even before you are ready to eat it. Trimming means removing the roots with some strong shears or snips so the bottom of the bulb is relatively flat and holds no obvious dirt. The top is cut off about an inch above the top of the bulb.
Cleaning is accomplished by rubbing the entire bulb in your hands and removing any loose wrappers with thumb pressure. There is a bit of an art to know when to stop removing loose layers. About all I can say is rub it until it looks its nicest, and then go no further.
If you are planning to make garlic braids with softneck type, you want to do it when they are about half-cured-- tops should be mostly dry but still supple enough to work with. If they get a bit too dry to braid easily, you can rehydrate them by misting the tops with water. Clean and trim the roots from the bulbs before braiding. After braiding, hang them up again to finish curing. If you add some dried flowers and do a nice job, your garlic becomes not only food, but a work of art!
Storage
The storage life of garlic is affected by the way it is grown and cured, the particular variety, and the storage conditions. Softneck garlic in general keeps longer than hardneck type. Garlic planted at the ideal time in fall, harvested at its peak and properly cured will keep better than garlic that suffered in its life.
The ideal storage conditions are low humidity, room temperature or slightly lower, and good air circulation. Softneck types are often good until New Year's and beyond. Hardneck types typically last only until Thanksgiving. There are heroic ways to extend shelf life somewhat with controlled atmosphere and temperature, but that only makes practical sense for large scale growers, and generally is not good for quality.
High humidity encourages the root nodules to swell and prepare for sprouting. Temperatures in the 35°-50° F range for extended periods mimic the outdoor conditions that initiate sprouting. Not good. Hot temperatures speed up the internal metabolism and cause bulbs to shrivel prematurely. Poor air circulation can lead to mold or accelerated decay processes.
Inside your refrigerator is the worst place to store garlic. It will start the sprouting process very quickly, and once started there is no turning back the clock. The exceptions to this rule are green garlic and uncured bulb garlic, which keep for a couple weeks in the fridge.
One good storage place to consider could just be in your kitchen, but away from heat sources and direct sunlight, on a counter where it is visible and you can admire it daily. That is, until it disappears into a delicious nourishing dish for you and your loved ones... and reciprocates the loving care you so selflessly provided in a way only garlic can do. Enjoy!
Matt has grown vegetable gardens in New Jersey, Illinois, Utah, Arizona and Oregon. His adventures in the business of agriculture began in 1986 with wildcrafting seeds of numerous native plant species in the desert Southwest for seed companies. This transitioned to establishing several community gardens and small market farms including The Farm at South Mountain in Phoenix, AZ; Native Seeds/SEARCH conservation farm in Patagonia, AZ; as well as his own HappyDirt Veggie Patch in Tempe, AZ and several other locations—moving to Ashland, OR in 2008. Happydirt has recently moved to Myrtle Point, OR.
Sourcing Garlic
If you are looking for a source of garlic seed locally, I recommend buying from Kimberly Brown at Here We Grow Gardens at the Ashland or Williams farmers market (link: https://www.herewegrowgardens.com/) Find her on Facebook (link: https://www.facebook.com/herewegrowgardens)
Or look for Eric and Ryan Navickas of UR Organic Farm at the Ashland Tuesday or Saturday Market.