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University of Illinois Extension
Herb Gardening

Garlic

Garlic

Allium sativum

Perennial

Description

Garlic is a member of the onion family.  It grows to about 15-18 inches tall and has flat leaves much like leek. There are two types of garlic; hardneck and softneck.  Hardneck varieties produce flower stalks and tend not to store well and may develop roots or start to dry out with a few months after harvest.  Softneck varieties do not produce a seed stalk. They are more productive and have a longer storage life of about 6-8 months. While hardneck varieties are often suggested for planting in northern growing areas, there are some softneck varieties suitable for planting in cold climates. 

Culture

Garlic grows best in a full sun location in soils that are well-drained and high in organic matter.  Fertility is also important as garlic has a moderate to high demand for nitrogen fertilizer.  Drought or excessively wet conditions will reduce yields.

Garlic is planted by separating the garlic bulb into individual cloves. The larger the clove often results in larger mature garlic bulbs at harvest.  Planting cloves from garlic purchased at grocery stores is not suggested. Often these bulbs were produced using varieties adapted to milder growing climates and how they have been stored is not conducive to good bulb formation. Plant the cloves about 2-3 inches deep.

Timing of planting is also important since optimum shoot and bulb formation development requires a cold treatment. Bulb formation and development is initiated in response to the longer warmer days of late May and June.  Garlic should be planted in the fall usually within one to two weeks after the first killing frost.  After planting, garlic develops roots, and shoots should emerge from the clove.  Plants may or may not be visible above the ground before winter.  Growth will resume in the spring.  Garlic is shallow rooted and is sensitive to dry soil so irrigation is important.  The most critical stage for supplying adequate irrigation is during bulbing, approximately May-June.  Irrigation should stop about 2 weeks before harvest.  Hardneck garlic will send up flower stalks called “scapes.” These are often removed to allow the plant to develop larger heads of garlic.  If removed before they straighten out, they are very tender and can be used in cooking. 

Harvesting

Different varieties mature at different times.  Harvesting too early results in small bulbs that don’t store well and harvesting too late forces cloves to pop out of their papery skins.  Harvest when the lower leaves start to turn brown.

Optimum harvest time is when half or slightly more than half of the leaves are still green.  Dig the plant carefully with roots and shoots intact.  Let the plants cure for about 3-4 weeks in a dry area with good air circulation.  After drying, the tops can be cut back to about one inch and the roots cut close to the base of the bulb.  Soil can also be carefully brushed away.  Store garlic in a cool area.  Properly cured softneck garlic will store for about 6-8 months while hardneck garlic stores for about 3-4 months.

Use

Garlic is used both cooked and fresh in a wide variety of dishes imparting a pungent taste.  It is also very aromatic.

Popular Varieties

Softneck Types

  • Inchellium Red – Large bulbs, mild flavor.
  • New York White – Has purple streaks and may also send up flower scapes (bolt).
  • Susanville – Stores well, large bulb size.

Hardneck Types

  • German Red – Popular hardneck variety for cold climates.  Large cloves.
  • Merrifield Rocambole – Similar to German Red except bulb is smaller.
  • Spanish Rojo – Good garlic taste.

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