Garlic is one of the most beloved ingredients in cooking and you can grow it at home! If you plant garlic this fall, you will have a bountiful harvest to look forward to next season.
Types of Garlic
Over its lengthy history of cultivation and selection, garlic has lost its ability to produce fertile seeds. Some varieties even lack a flower stalk, or scape, and as such is usually distinguished as either hardneck (with scape) or softneck (without scape).
Hardneck garlic, Allium sativum var. ophioscorodon, also referred to as topsetting or bolting garlic, produces a distinct scape when growing. Hardneck bulbs typically have 4-12 cloves surrounding the scape and include varieties such as Killarney Red, a great easy-peeling variety with a strong and nutty garlic flavor.
Softneck garlic, Allium sativum var. sativum, sometimes referred to as “artichoke” garlic, does not produce a scape and is generally more productive than hardneck garlic as softneck do not expend any energy into scape production. Each softneck bulb generally contains between 10 and 40 cloves arranged in layers, available in many varieties including California, an easy to grow, mild garlic variety.
Elephant garlic, Allium ampeloprasum, is not a true garlic, but is a type of leek, growing much larger than true garlic generally with bulbs consisting of 5 to 6 cloves weighing as much as one pound per bulb. This type of garlic generally has a much milder taste than true garlic, though it can sometimes become somewhat sharp in cooler climates.
Preparing the Garden
For best results, garlic should be grown in rich well-drained soil, performing best in sandy loam or loam soils. It can be helpful to conduct a home soil test using a test kit to get an idea of soil pH and nutrient levels so that you may properly prepare your bed. Garlic generally prefers a soil pH between 6.0 and 7.0, though acidic soil can be amended with Garden Lime to raise pH and Soil Acidifier can help to lower the pH of alkaline soils. Additionally, soils should be well-tilled prior to planting.
As garlic requires a great deal of nutrients to grow, especially nitrogen, amend your soil prior to planting so that the cloves have what they need to establish. Blood Meal provides a source of nitrogen. Additionally amend with Bone Meal and Potash as needed for sources of phosphorous and calcium, and potassium, respectively. Working compost into the soil to aid in organic matter content will also provide needed micronutrients for optimal growth. After the garden is prepared, it’s time to plant.
Garlic should be planted in the fall, one to two weeks after the first killing frost. This generally falls around the third or fourth week of September in northern Minnesota, and around the first or second week of October in southern Minnesota. This timing ensures that roots are developing, and shoots are emerging from the cloves, though still below the soil, at the time of the first hard freeze (28F). When you are ready to plant, wait to separate individual cloves from the main bulb until the day of planting. Leave their skins on.
Plant cloves pointy side up, two to three inches below the soil surface. Space cloves at least six inches apart. Space your rows at least 30 inches apart for best results. Closer spacing will result in higher yield but smaller bulbs. Larger spacing will result in lower yields but larger bulbs.
Mulching and Irrigation
After planting, garlic should be covered with a fluffy layer of straw, marsh hay, or chopped leaves at least six inches deep before winter This wil moderate soil temperatures and prevent damaging freeze-thaw cycles. In the spring, mulch should be removed after the threat of a hard freeze (28F) has passed, usually around mid-April, at which point you should also see shoots emerging. New shoots can tolerate temperatures down to 20F. Gardeners will often remove the layer of mulch to allow the ground to heat up, and then reapply once shoots are about six inches tall. The reapplication of mulch helps compete with weeds and helps to conserve moisture which is important as garlic has a relatively shallow root system and is sensitive to dry soil conditions. This is also a great time for an additional application of nitrogen.
Proper watering is crucial during bulbing, generally from the end of May through mid-July. Be sure to remove scapes from hardneck garlic as they begin to curl, generally in early to mid-June, to improve yield. Stop watering about two weeks before harvest to avoid stained bulb wrappers and disease.
Harvesting your Crop
Harvest time for garlic in Minnesota typically extends from mid-July through the first week of August. Begin monitoring for browning of the lower leaves in June and consider harvesting when half or slightly more than half of the leaves are still green. To test if they’re ready, pull a few bulbs and cut them in half; if the cloves fill out their skins, then it is time to harvest.
Plants should be dug out entirely intact. Try to harvest when your soil is dry and use a shovel or pitchfork to gently loosen the soil. Do not pull up plants by their necks. For most, it is easiest to wash your bulbs the day of harvest before curing, though you may also brush off the soil after curing if you prefer.
Curing and Storing Your Harvest
For curing, tie plants in bundles of five to ten and allow to dry in a warm (55F-65F), dry (less than 60% relative humidity), well-ventilated room, pantry, or closet out of direct sunlight. Place on a rack in a single layer or hang to cure for three to four weeks. After curing, cut the shoots to an inch above the main bulb and trim roots back to the base of the bulb. Clean cured bulbs by removing the outermost skins and any remaining soil, taking care not to expose any cloves.
For garlic you plan to eat, it is best to store bulbs at 32F-40F with 60-70% relative humidity. Garlic may also be stored at room temperature, but this will cause bulbs to dehydrate more quickly. Softneck garlic can generally be stored for six to eight months at room temperature, while hardneck garlic usually starts to deteriorate after about three to four months, though if kept at 32F, it may keep for up to seven months without significant dehydration. If you plan to save garlic to plant next fall, store bulbs at room temperature at 60-70% humidity to ensure proper bulbing.