How to Grow Garlic

Start with Quality Garlic Seed

Garlic seed is a misnomer. While its wild ancestors and early cultivars produced true seeds, Allium sativum is now so domesticated that it has lost its ability to do so. Whenever you read sativum in a plant’s Latin name, you know it’s a domesticated species.

What defines seed garlic from culinary garlic is the size of the bulb. Seed garlic is generally more than two inches in diameter, while culinary is less than two inches. There’s plenty of opinions regarding which garlic bulbs to use as seed, but the science takes virtually all of the folklore and guesswork out of the equation. Results from numerous experiments show the weight of a garlic clove is the variable that most affects the size of the bulb harvested.[1]

Garlic does not sexually reproduce unlike many other crops. Seed production is an evolutionary adaptation that allows a species to break the pathogenic infection cycle. For this reason alone, it is incredibly important to buy garlic from trusted seed growers that test for plant pathogens on a yearly basis. We do! Order Here with FREE SHIPPING. Many garlic seed companies do not test their seed garlic for fungal, bacterial or animal pathogens. Do you really want to take the risk?

The most infamous fungal pathogen is white rot (Sclerotium cepivorum), which produces tiny poppy seed-looking structures called sclerotia. These sclerotia are incredibly resistant to environmental degradation, and can survive in a soil for decades. One tiny sclerotia per kilogram of soil can cause significant crop loss. White rot is marked by white mycelium growing in and on your bulb. There is no current treatment for white rot, which is why it is vital to buy clean garlic seed. White rot will infect any allium crop you grow in the infected soil, including onion, chives, and leek .

Another common fungal pathogen is Rhizoctonia solani. It’s common name is root rot, though many other fungi and bacteria can cause a root to rot . Rhizoctonia is marked by reddish to brown lesions found on the roots or bulb. Like with white rot, an infected bulb will begin to wilt, and the older, lower leaves will begin to yellow until the entire plant succumbs to the same fate. If you find infected bulbs, remove them immediately and dispose of them in the trash. In another blog post, I will discuss in detail how to protect your crops without the use of toxic pesticides.

Garlic Planting Season

The most common question I receive from fellow garlic growers is when to plant their garlic. I wish it was as easy as telling you all a date to plant, but it is more nuanced. A grower in Northern Montana does not plant at the same time as a grower in Texas.

It is not recommended to plant garlic in spring. Planting garlic in summer won’t work at all. Garlic planting season is early fall to early winter, depending on your local climate and latitude.

      The best advice I can give a grower is to figure out when their soil generally freezes and work back from there. Plant your garlic 4 to 6 weeks before the ground freezes. I grow in Montana in zone 5a, and I plant my garlic the second week of October. I’ve planted as early as October 7^th, and as late at Halloween. If your ground freezes, you want to give your garlic enough time to put down its roots so frost heaves do not pop all of your cloves out of the ground!

     Above is our garlic field under 6" of snow. They didn't even bat an eye!

    If your ground does not generally freeze in the winter, you can plant anytime from November to January. My sister in Texas has planted as late as January with great success. One must understand garlic as a cold-season crop, requiring a vernalization period in order to grow properly and size up its bulb. This is fancy talk for exposing your garlic to cold soil temperatures. It usually need about 6 weeks of cold temperatures (40F and below) throughout the winter.

Soil Preparation for Garlic

     Garlic appreciates soil that is friable, which means it shouldn’t feel like concrete when planting into it. Very tight soils can cause deformed bulbs, and can make it incredibly difficult to harvest. Why give yourself the headache?

     For home gardeners, prepare your soil 1 to 4 weeks before planting. If your plot is full of weeds, I recommend starting your soil prep closer to 4 weeks before planting. This gives the soil enough time to start decomposing the plant matter. You want your soil to be loose so it is a joy and not a chore to plant.

Garlic Planting Depth and Spacing

    Planting garlic is incredibly easy, but requires a few bits of knowledge in order to get it right. First, always plant your garlic in the correct orientation with its root-side down. If you are unsure which side the roots come out of a clove, hold a garlic bulb in your hand. The fatter side of the garlic should be resting on your palm. This is where the basal plate is located, and is from where the roots grow.

    Plant your cloves so that the upper tip is between 2-4” below ground. Any deeper, and you run the risk of poor emergence. You can either dibble a hole with a blunted wooden dowel or use a trowel to do the same. Garlic Spacing is 4-6” within each row and 16-24” between each row. Cover with soil and voila!

   Below you see that we make furrows in the soil to make it easier to plant 40,000 cloves. It takes us about a week.

 

Mulching Garlic

     The short answer is no. Most commercial growers do not mulch because of the headache it creates during the season. (Think about mulching 100 acres!) We grow in zone 5a where winter temperature can get down to -20F. We do not mulch and our garlic does not care one bit. If I was a home gardener, I would only consider mulching if I lived in zone 4 or below.

      If you do decide to mulch, make sure you do not mulch more than a few inches. Otherwise, the garlic will have a difficult time growing through it come spring. It can also cause damage to the leaves as it tries to emerge. Another option is to remove the mulch once the soil thaws in late winter/early spring. This allows your soil to warm, which triggers your garlic to start poking through the soil. Once your garlic is 6 inches tall, you can re-mulch around them if you are worried about weed and soil water retention. This is especially important if you are growing garlic in raised beds, as raised beds are notoriously quick to dry.

       Make sure whatever mulch you use has not been treating with herbicides. Certified “weed-free” hay or straw is almost always treated with herbicides, which can damage or kill your garlic. I recommend using straw over hay. Woodchips are not recommended.

Best Fertilizer for Garlic

While some garlic growers fertilize at planting, I do not recommend it. Winter soils do not need any fertilizer. Nothing is growing! Soluble nutrients, such as nitrogen, potassium and sulfur, will inevitably leach out of the soil profile during the wet winter months. It is a waste of money and resource. With that said, you can apply compost during the fall planting season.

My best recommendation to all growers is to learn what it means to balance a soil’s nutrients. The only way to predictably and accurately fertilize any crops is to learn how to conduct soil tests and interprate the results. We use Midwest Laboratories out of Omaha, Nebraska, but any local university extension offices also provide soiling testing.

We fertilize our garlic in early spring with nutrients based upon our soil tests. There is no need to add more phosphorus, for example, if our soil is sufficient. Overfertilization not only can cause ground water pollution but can actually inhibit your plant’s uptake of other nutrients. This is why it is vital for a home gardener to learn how to properly fertilize. Simply going to your local hardware store to buy some Mircale-Gro and dumping it on your soil is not a sustainable strategy.

When you do go to fertilize, DO NOT OVERFERTILIZE WITH NITROGEN! This is one of more problematic practices out there. Not only can it reduce your soil’s organic matter content, it will also reduce bulb size, spur weed growth and pollute our waterways.

If you are unsure about how much fertilizer you should use for your garlic, start will the low end of the fertilizer recommendations you find on the bag. Wait two weeks to how your garlic responds, and either add a bit more or leave your garlic alone. If the plant looks healthy and green, why waste your money by adding more fertilizer?

Garlic Harvest Time

This one can be a bit tricky. For hardneck garlic varieties, you will want to harvest the garlic scapes as they begin extend beyond the leaves. Hardneck varieties include Music, Chesnok, German Extra Hardy, German Red, Korean Red, and more. Here in zone 5a, hardneck garlic starts to scape about the first week of June. Four to six weeks later, I know my garlic is ready to harvest. Softneck garlic varieties do not produce scapes, so this strategy does not work. Softneck garlic varieties include Inchelium Red, California Late, Red Toch, Silverskin, Early Italian, and more.

The best way to know when to harvest your garlic is to sacrifice one for science! Harvest one of your plants and cut through the cloves from the side. When the cloves have filled out the space inside the bulb (see photo below), your garlic is ready. See how all the cloves are tightly packed?

One quick note: make sure to reduce irrigation about four weeks before harvest, and completely stop watering two weeks before harvest. This triggers your garlic to go dormant. We want that! Garlic is not a summer crop, and hates to be watered during this time period. Over-watering during this time period increases the risk of infection. Believe me, I’ve learned this the hard way.

Curing Garlic

Curing garlic is important for maintaining quality bulbs during storage. Some people hang their garlic from barn rafters, while others spread them over a table. So long as there is good air flow, this does not matter. Cure your garlic out of direct sunlight in a well-ventilated space that does not get too hot. Open garages and porches are great places. If you do not have either, make sure to run some fans so the air is not stagnant. Also make sure the humidity is not too high, or your garlic may mold. Keep humidity below 70% and keep temperatures between 60-80F for proper curing.

Storing Garlic

Garlic is best kept away from sunlight. Commercial growers store their garlic long-term at temperatures between 30-32F in a well-ventilated space. However, these are specialized facilities and is not practical for the home gardener. Do not store your garlic in the fridge. The moisture in a fridge will cause your garlic to sprout prematurely. Do not store your garlic between 40-55F, as this will also cause sprouting. At home, the best place to store them is in an open pantry or basement that is not excessively humid. 55-65F and 45-65% are the ideal storage temperatures and humidity for the home gardener. Under ideal conditions, garlic will last 4-12 months. Softneck varieties tend to store longer that hardneck varieties.

              I hope all this information helps all my fellow garlic growers in their pursuits. If you have any questions, please feel free to reach out via email. I get a kick out of helping everyone become a better grower. Best of luck!