Don't plant grocery store garlic
Garlic (Allium sativum L.) is closely related to onions and chives and is used as a medicinal and culinary herb. Garlic is growing in popularity as we become more accustomed to its flavor and knowledge about its many health benefits. Garlic forms bulbs, which separate into cloves, each covered with a white-purplish or pinkish, papery sheath. It is the cloves of garlic which are planted for propagation. Purchase cloves for planting from national or local garlic seed producers. Garlic purchased at the grocery store usually used to season food is not recommended. This garlic, primary softneck varieties, is grown in a mild climate like northern California. The type of garlic grown in Minnesota requires a cold treatment.
There are two categories of garlic-hardneck and softneck types. The hardneck garlic has a stiff, sometimes thick neck, and usually has fewer, larger, even-sized cloves arranged around the central neck. The number of cloves vary from four to 12. Typically the fewer the cloves the larger they are. Hardneck varieties produce a flowering stalk, called a scape, while softneck varieties do not. Flowers on scapes usually abort and form "bulbils," or small, aerial cloves. Scapes can be removed just after they start curling, and can be eaten. More mature scapes can be used in flower arrangements. Common hardneck varieties are Rocambole, Purple Stripe and Porcelain.
Softneck varieties produce more cloves. Usually there is a row of larger cloves on the outside and inside these are several thinner, smaller cloves. While softneck produce more cloves, many of them are small and thin. Since the neck is soft, this type can be easily braided for storage. Common softneck varieties include Artichoke and Silverskin.
Garlic in Minnesota should be planted in the fall -- usually within one to two weeks after the first killing frost (32 degrees). In northern Minnesota, planting during the third and fourth week of September is recommended. While in southern Minnesota, planting around the first or second week of October is recommended. Ideally, roots should be developing and shoots should be emerging from the clove but not above the soil at the time of the first hard freeze (28 degrees F.). Garlic shoots will emerge from the ground in late March or early April. Unless given a proper cold treatment prior to planting, garlic planted in the spring will often produce weak shoots and poorly developed bulbs. Lack of scape development in hardneck garlic, and bulbing in all garlic, is usually due to an inadequate cold treatment.
The amount of garlic to purchase will depend on the area to be planted, spacing, and variety. Some varieties have more plantable cloves per bulb than others. Generally, there are about 50 cloves per pound of garlic. Therefore, garlic spaced at six inches apart within a row, 100 feet in length will require approximately four pounds of cloves. Individual cloves should be separated a day or two before planting. If you are planting cloves from this year's garlic crop, use the biggest cloves. Plant cloves pointed side up, with the base of the cloves 2-3 inches from the soil surface, with 6 inches between each clove. If you are planting a double rows, they should be 30 inches apart. Garlic grows best in well-drained, moisture-retentive soils high in organic matter. Well-rotted manure or compost are ideal soil amendments. Optimum soil pH for garlic is between 6 and 7.
Beds should be covered with 3-4 inches of leaf or straw mulch to prevent fluctuating temperatures during winter and early spring, and to help control weeds. The mulch can be removed in the spring after the threat of hard freezes is over to help the soil warm up, or it can be left in place to help weed control and preserve soil moisture. Garlic roots are very close to the surface of the soil and they do not compete well against weeds, so if you do not keep the mulch on, frequent, shallow cultivation will kill weeds before they become a problem. Adequate water enhances good production. Soak the soil thoroughly when watering, to a depth of at least 1 inch per week during the growing season. Stop watering two weeks before harvest to avoid staining bulb wrappers and promoting diseases.
Harvesting too early will result in small bulbs, and harvesting too late will result in cloves popping out of bulbs. Depending on variety and climate zone, garlic is normally harvested between late June and late July. One indication to start harvesting is when the lower leaves turn brown and when half or slightly more than half of the upper leaves remain green. You can pull a few bulbs and cut them in half, if the cloves fill the skins, the bulbs are ready to harvest.
Harvest plants with shoots and bulbs attached. Knock off any large clumps of soil, and put them in a warm, dry, airy place for 3-4 weeks to cure. This will dry the sheaths surrounding the bulbs, as well as the shoots and roots. After curing the shoots can be cut ½ -1 inch above the bulbs and the roots trimmed close to the bulb base for hardneck varieties, and stored for several months at temperatures under 40 degrees. Softneck varieties shoots do not need to be cut off but can be braided and stored at room temperature for several months.
Kyle Schulz is a Wadena County Master Gardener from Sebeka, and the regular gardening columnist for the Wadena Pioneer Journal.