on when to plant
"My neighbor gave me a few heads of garlic.
When should I plant the garlic? Spring, Summer, or Fall?"
In simple terms, we can divide the garlic world into two groups, hardneck, and softneck. Garlic is separated into these two categories based on numerous subtle factors including the presence or absence of a flowering stalk, the clove-formation pattern, and hardiness.
Hardneck garlic typically produces a flowering stem called the garlic scape. The “neck” is the stem that grows through the center of the cloves. This stem is very rigid and tough, hence the name "hard neck". The hardneck garlic bulb or head is made up of individual sections called cloves. The cloves are similar in concept to sections of a mandarin orange. Hardneck garlic varieties tend to do best in colder climates as they are more winter-hardy. They typically grow well in the northern hemisphere of the United States. Many gardeners find that hardneck garlic is more flavorful than its softneck counterparts. There are numerous named hardneck garlic varieties, including 'Music', Rosewood, ‘Siberian‘, ‘Metechi‘, ‘Purple Glazer‘, and ‘Spanish Roja’. Hardneck garlic requires vernalization (exposure to cold temperatures for at least a few months or longer) which stimulates root development, sprouting and bulbing. Gardeners in cold climates usually grow hardneck. Their goal is to reproduce! They form a bulb with cloves, and an umbels with Bulbils. When you allow hardneck garlic to develop a scape (flower stalk), you get what is called an Umbel. The umbel (or flower) contains tiny cloves called bulbils. These little bulbils can be eaten just like a clove of garlic, or planted.
Softneck garlic typically lacks the garlic scape structure and the stem of the softneck garlic is much softer than the stem of the hardneck garlic. Softneck garlic can be easily braided together when dried. Softneck garlic normally grows best in climates with warm summers and mild winters. Gardeners in warm climates usually grow softneck. There are numerous named softneck garlic varieties including ‘Nootka Rose’, ‘Viola Francese’, and ‘Inchelium Red’.
Hardneck Garlic Needs Exposure to Cool Temperatures
Hardneck garlic needs to be exposed to at a few months (3-4 months is ideal) of cold temperatures below 40-45 F to develop beautiful and robust bulbs. This is called vernalization. Why do plants need vernalization? Hardneck garlic evolved in colder climates. These plants take advantage of cold conditions to synchronize their growth and bulb development.
When to Plant Hardneck Garlic?
Hardneck garlic should be planted in the fall, about 6 weeks before the first frost. The cloves should be planted 2-3 inches deep and 6 inches apart. Hardneck garlic needs to have a cold winter in order to grow properly. If you live in a warm climate, you can try planting hardneck garlic in the spring, but it may not grow as well.
Here are some tips for planting hardneck garlic:
Choose a spot in your garden that gets full sun.
Amend the soil with compost or manure.
Plant the cloves with the pointed end up.
Water the cloves well after planting.
Mulch around the cloves to help retain moisture.
Be patient! Hardneck garlic takes about 9 months to mature.
Hardneck garlic is typically planted in the fall (between late September and November) and harvested in the following summer (between June and August). In areas that get a hard frost, plant garlic cloves about 6 weeks before the ground freezing. In Montana, we've planted hardneck garlic cloves as late as December. In cold climates (northern hemisphere of the United States), hardneck garlic is typically planted in the fall.
John Swenson, Garlic Seed Savers, recommends that growers monitor the soil temperature." When the soil temperature drops to 60 degrees Fahrenheit, start planting your garlic. Science has shown that to be the optimum temperature for the termination of roots from the stem of the garlic clove. For most of North America, that’s early October." Plant hardneck garlic cloves before the ground freezes, as this will give the cloves time to establish a root structure. Ideally, plant hardneck garlic about 4-6 weeks before the ground starts to freeze. Contact your local extension service or nearest University or College to determine the average soil temperatures in your area. Plant the cloves with the "pointy side up". Space the cloves six+ inches apart in all directions and three to four inches deep. Hardneck garlic bulbs (aka garlic heads) should be taken apart into separate cloves before planting. Popping the cloves is an easy way to separate the cloves. WATCH POPPING GARLIC HERE.
Planting Too Early?
Planting hardneck garlic cloves too early is a common mistake. By planting too early, there is a possibility the garlic may suffer from poor bulb development and smaller garlic cloves. By planting cloves too early, the garlic clove will likely expend some of it's finite amount of energy to establish green shoots and leaves. Garlic establishes it's root structures before it establishes the green shoot. If the garlic cloves are planted too early, the green shoot can grow several inches. If the winter conditions are exceptionally cold, the green shoots can be damaged. These shoots can also act as a conduit during the winter, drawing water from the clove, and resulting in the death of the delicate clove. By planting too early, the cloves may be exposed to warm soil conditions, which can reverse the vernalization process, resulting in smaller bulbs. If your region receives abundant fall rains, the cloves could also develop mold and rot. If the green shoots die back in the winter, the yield will be decreased from the theoretical possibility, as energy stored in the garlic clove will have been wasted. When properly planted, hardneck garlic cloves (seed garlic) can withstand winter lows of -40°F. If planted too early, too much tender top growth happens before winter.
Planting Too Late?
If planted too late, the clove may not be able to establish roots and may "bubble up" to the surface of the soil. Roots help anchor the clove in the soil and help prevent the clove from "rising up" due to frost heaves. These exposed cloves may be more susceptible to winter damage and exposure to winter sun rays. Ravens and Magpies have been observed playing with and flying off with cloves that "bubbled up" to the surface during the winter. If planted too late, there will be inadequate root growth before the winter, and a lower survival rate as well as smaller bulbs.
Planting Garlic in the Spring?
Spring is typically the time of the year most gardeners plant vegetable seeds such as carrots, peas, and squash. Springtime is not the best time of the year to plant garlic. You can grow a tasty crop of green garlic or you can grow it to produce bulbs. Green garlic, also called spring garlic, is similar to scallions. The garlic plants form slender stalks with brilliant green leaves and tiny bulbs. The soft, tender leaves and stalks are flavorful and delicate. To plant green garlic, plant garlic cloves in the garden as soon as the soil is workable and not frozen. Plant the cloves about 2" deep, 6" apart, with the pointy end of the clove facing towards the sky. Begin harvesting the shoots and leaves while they are still soft and delicate.
The main reason gardeners grow garlic, however, is for bulbs. It’s important to remember that your spring-planted garlic bulbs will likely be smaller than those planted in the fall. Just remember to plant your next crop of garlic in the fall! Hardneck garlic planted in the fall get's a critical head start on the growing season. Fall-planted garlic is harvested in early to mid-summer (the end of July), depending on your region. Spring-planted garlic requires additional time (a couple of extra weeks) to catch up. Plan to harvest spring-planted garlic in late summer, depending on your region.
Although garlic is typically planted in the fall, if you missed the fall planting, you can still attempt to grow garlic, but there is an important step you'll need to take first. The secret to growing large bulbs from spring-planted hardneck garlic is easy but requires a simple time-critical step. The important secret is to expose the garlic you intend to plant, to cold conditions for a few months. Hardneck garlic establishes large bulbs and cloves if the planted clove can experience a period of colder weather—at least 40˚F (4°C). To vernalize hardneck garlic, place the planting stock in a refrigerator for a few months. Put the cloves in a brown paper baggie and keep a check on the garlic often to make sure it does not spoil. The refrigerator should be dark and have a temperature of 35°F to 45°F. Never put garlic bulbs in the freezer. If you do have to share a refrigerator with any food, make sure that there are no apples or pears because they emit ethylene gas that may encourage bulbs to decompose. Some bulbs may develop a blue-green mold during the process of pre-cooling. A firm bulb is a viable bulb. Discard any that are soft after pre-cooling. Once planted, the soil wicks away excess moisture and the mold should disappear. If you see mold, you may wish to "pre soak" the garlic in an alcohol or hydrogen peroxide solution.
Tips for Southern Growers. Prechilling!
If you live in a southern region of the United States (Florida, Georgia, Texas, etc..) and you want to grow hardneck garlic, give your seed garlic the cold treatment prior to planting. This cold treatment involves putting your garlic in a paper bag in a refrigerator. The refrigerator should be dark and have a temperature of 35°F to 45°F. Never put garlic bulbs in the freezer. *** If you do have to share a refrigerator with any food, make sure that there are no apples or pears because they emit ethylene gas that may encourage bulbs to decompose. Some bulbs may develop a blue-green mold during the process of pre-cooling. A firm bulb is a viable bulb. Discard any that are soft after pre-cooling. Once planted, the soil wicks away excess moisture and the mold should disappear. If you see mold, you may wish to "pre soak" the garlic in an alcohol or hydrogen peroxide solution. Before removing the bulbs from refrigeration, prepare the planting site fully. Remove only the seed garlic needed for immediate planting. Do not remove them from the refrigerator and leave them out in the sun in advance of planting. They could lose their cool. It’s all right to prechill the bulbs a little longer than specified, but never shorter. This "Simulated Vernalization" is a period of prechilling the bulbs. In horticultural zones 7 through 9, this means that the bulbs should be prechilled at a dark 35°F to 45°F for up to 16 weeks. The longer vernalization period of three+ months has the potential to allow southern gardners to grow hardneck garlic successfully!
At GROeat Farm, we store seed garlic in a cool room between 42 - 50ºF with 60% humidity. Purchase seed garlic as soon as it is available in September, and place the garlic in the refrigerator as soon as possible. Mark your calendar to "alert you" to receive the garlic a few months later. Plant after that. If your southern region receives abundant rainfall, the planted garlic cloves may rot or mold. Be sure the soil is not kept too moist. Planting in raised beds with "fluffy", well-drained soil is a good option here.
***Don't place garlic in a freezer, unless you are able to set the freezer's temperature to just at freezing or above.
Garlic Needs Good Soil
Garlic grows best in "fluffy" well-drained, moisture-retentive soil with a pH between 6.0 and 7.0. Plant cloves in the fall, usually one or two weeks after the first killing frost. Unless you control weeds early, they can easily overtake young garlic plants. Insects are not a major problem with garlic, although onion maggot is a potential pest. Hardneck garlic appears to do well when grown in fertile soil with lots of organic matter. Garlic plants are heavy feeders. In other words, garlic requires a full range of nutrients and full-sun exposure. If you have not performed a soil test and If soil fertility is uncertain, growers of hardneck garlic may provide the plants nitrogen (N) every two weeks in early spring until there are four leaves. Do not use fresh manure as it may contain harmful bacteria and may increase weed problems. Prior to planting, be sure your soil feels loose and "fluffy". Garlic has a moderate to high demand for nitrogen. A large robust garlic plant typically produces large a large bulb. Don't over-fertilize.