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Garlic for the Home Garden
FS 138
Reprinted May 2003
N.S. Mansour
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Garlic grows well throughout the Northwest. There are two types of garlic frequently grown in home gardens: Allium sativum, the more commonly cultivated type, also called silver-skinned or Italian garlic; and Allium ampeloprasum, usually called great-headed or elephant garlic. The latter is more of a novelty because of its large size. There are many special selections or clones of each.
Garlic is not grown from seed. Bulbs used for planting stock are available from several vegetable seed catalogs and local seed companies. Shopping from several catalogs provides opportunities to collect different strains. Although fresh garlic bulbs available in grocery stores and produce markets also may be used for planting stock, such material may be infected with and can transmit serious diseases and nematodes.
Allium sativum "California" strains of garlic can be classified on the basis of maturity as early or late, referring to the speed of sprout emergence after planting, and subsequent bulbing and maturing. Garlic also may be classified as bolting (or flowering), incomplete bolting, or nonbolting.
Great-headed or elephant garlic is the least pungent garlic, followed in rank by early and late Allium sativum in ascending order of pungency. There are minor variations among individual selections.
Garlic is a bulbous plant related to onion, chive, and leek. The leaves of garlic have solid, thin blades rather than the more round, tubular, hollow blades of onion leaves. As garlic matures, it produces a fairly smooth, round, dry bulb at the base. Each year common garlic divides into cloves (usually 10 or more) soon after bulbing.
Most bulbs of great-headed or elephant garlic grown from the larger cloves divide at the end of one growing season, but many bulbs grown from the smaller cloves remains as one solid bulb or large clove called a "round." The stem of the plant is attached to the top of the "round" rather than to the root plate. A "round" planted back the second year will produce a plant, the bulb of which will segregate into a few very large cloves.
Small, round, very dormant cloves completely enclosed within thick, hard, brown, protective leaves may be found at the base of mature elephant garlic bulbs. Instead of using these small cloves as planting stock, it is better to use them for pickling after removing their leaf cases.
Preparation for planting
Garlic plants have large and well-developed root systems that reach to depths of more than 3 feet in well-drained soils of the Willamette Valley. Clay loams are better for garlic than sandy soils, provided there is good surface drainage during winter. Surface drainage is improved by planting garlic on beds raised 6 to 8 inches above the natural level of the garden.
Before planting, mix a complete fertilizer (such as 8-24-8) thoroughly with the top 8 to 10 inches of soil. Apply 2 pounds of fertilizer to 100 square feet of soil. In late April or May, sidedress the plants with 1/2 pound of ammonium sulfate to 100 square feet. No additional fertilizer is required in most soils.
Select clean, dry bulbs. Carefully break them apart into individual cloves. The bulbs will separate naturally into two sizes of cloves. The larger ones are preferred for planting stock. Do not bruise the cloves. Plant the cloves the same day they are "cracked" (broken apart).
Planting
Plant cloves 1 to 3 inches deep anytime from September through November for best results. During fall and winter, the root system develops and a little top growth is made. By spring, the plant already is well established and makes rapid top growth as the weather warms. Large, vigorous tops are necessary to produce large bulbs.
Plant garlic in the open where it will receive full sunlight and no competition from perennial plants. To save space in a small raised bed, plant the cloves 3 to 4 inches apart in rows 6 to 8 inches apart. Elephant garlic should be spaced 4 to 6 inches apart in rows 8 to 12 inches apart. If space is not a problem, garlic may be spaced more widely or planted in a single row through the garden.
Plant so that the tops of the cloves are 2 inches beneath the surface of the soil. Planting the cloves with the root end down is not necessary. The clove used as planting stock disintegrates during winter as the plant grows.
Care of plants
Garlic, like onions, cannot withstand weed competition. Use very shallow cultivation with a sharp hoe to keep the area scraped free of weeds. Many roots of garlic are near the surface of the soil; damaging them will reduce yields.
Provide enough water during spring and early summer to moisten the soil thoroughly to a depth of 2 feet every 8 to 10 days. Stop irrigation as soon as the first plants begin to mature (the tops fall over naturally and become dry).
Thrips usually can be found on garlic leaves throughout the summer, and they are more damaging than generally realized. Thrips give the leaves a silvery, streaked appearance and may be seen as tiny brownish "threads" along the mid-ribs.
Harvesting
After all the tops have dried or fallen over, the bulbs are ready to harvest. This occurs in late August in Oregon. Lift the bulbs carefully with a trowel or spade and place entire plants in the shade to dry for a week or more. After drying, clip off the tops and roots (1 inch from the bulb) or leave the plants intact with the tops of several plants braided together. Gently free the soil from the roots. Handle carefully. Garlic deteriorates rapidly if bruised.
Storage
Garlic may be stored in a mesh bag or slated crate or hung in braided ropes or bunches from rafters. Any cool, well-ventilated place will do for storage through the winter months. In very cold areas, the bulbs should be protected from freezing.
Save the largest and best-formed bulbs for planting.
Prepared by N.S. Mansour, Extension vegetable crops specialist emeritus, Oregon State University.
Revised January 1998. Reprinted May 2003.
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