Do not plant where Alliums (onions, chives, garlic) have been planted in the previous 3 years. Always rotate where the garlic is planted each year sticking to a 3-4 year crop rotation. It is also a good idea to have a soil test done each year to determine your soil's needs. Garlic does best with a soil pH close to neutral (7). Contact your local university extension office for more information of how to get your soil tested.
Planting time is in the fall a few weeks before frost, usually mid to late October for us. What we try to do is plant early enough so the cloves starts to grow roots and get a good hold in the ground but late enough that the plant does not send too much of a top sprout above the ground before it goes dormant for the winter. We recommend planting the cloves in hilled/mounded up rows. This allows for them to not sit in standing water if we get lots of rain, melting snow in the spring, etc. Plant cloves about 3 inches deep and about 6 inches apart. Be sure to have the clove bottom, where the bulb roots were, face down when planted otherwise if planted upside down or sideways the plant will have a hard time righting itself and you will get a smaller deformed bulb next summer.
At planting time in the fall you can add some fertilize to give them a starting boost. We soak our cloves in a fish emulsion foliar fertilizer, baking soda, and water mix for 12-24 hours the day before we plant. The baking soda helps to kill any fungus spores that may have been on the wrappers. Next soak the cloves in rubbing alcohol or vodka for 5 minutes right before planting the cloves as this will help kill any pests or pest eggs that also may have been on the wrappers. In the spring once the plants are 8-12 inches tall spray the plant leaves with a fish emulsion foliar spray fertilize or other organic fertilizers to give them another boost. Re-apply about 4 weeks later.
In the fall It is also very important to add a few inches of mulch (straw, leaves, etc) over your hilled/mounded rows as this will help over the winter by preventing freeze/thaw cycles and frost heave then the mulch will help with controlling ground moisture and weeds the following summer. As the mulch breaks down it will help add more organic material to your garden. Keep the garlic weeded as they do not compete well with weeds. If the summer is dry do a deep watering once a week. Stop watering several weeks before harvest.
In early to mid June you should see a top stalk like shoot grow up from the middle of the plant, this is called a scape, it will grow up about 12 inches and then curl down and make a loop. Once it curls down and starts to make a loop cut or snap it off right above the upper most leaves on the plant. This scape is edible and very delicious. It has a mild garlic flavor and a texture similar to asparagus. It can be prepared much like your asparagus by sautéing in olive oil or grilling. They are also great to use in making pesto. Cutting the scape off allows the plant to put more energy into growing the bulb bigger vs growing out the scape which if left uncut will grow rather large and tall and your garlic bulb will be much smaller. By leaving the scape on you can also collect the small seed type bulbils to use to plant more garlic in the fall potentially expanding your number of plants more quickly. These small bulbils will produce a small garlic round or bulb the next year and if re-planted for several years will give you normal full size bulbs.
The bulbs should be ready to harvest in early to mid July. What you will want to look for is when the leaves start to die back. When about half the leaves have died back go ahead and dig them up. Do not pull but use a pitch fork to loosen the dirt around the bulb first. If left in the ground too long the bottom of the bulb can start to rot and too many paper wrapper layers will be lost.
Once harvested keep the bulbs out of direct sunlight and hang them in a dry area with good air circulation for 3-4 weeks. Do not rinse dirt off the bulbs or cut the stalks off the plant before hanging. Bundle and tie about 10 plants together so they can be hung to cure. You can hang in a barn or garage and use a fan for good air circulation. After 3-4 weeks and the plants have completely dried down and turned brown you can then cut the bulb off the stalk about an inch up and trim back the roots so that they are very short. You can then clean off a wrapper layer so the bulbs are clean and ready to be stored inside in cool dark area.
Visit https://www.gourmetgarlicgardens.com for a great additional resource for all things related to garlic.
Garlic Growing FAQs
Hardneck garlic varieties grow well in the colder climates of the Northern United States and Canada and are well adapted to survive cold snowy winters. Your best option is to try and buy your garlic bulbs for seed from a reputable grower in the same Plant Hardiness zone as you located so the garlic is accustomed to your climate. Otherwise it may take a few years for the plants to become accustomed to your climate before they start to really flourish. These zones can be viewed here: http://planthardiness.ars.usda.gov/PHZMWeb