Garlic

July/August 1995

By Ronald E. Voss, Director, Small Farm Center

Garlic, Allium sativum, has become an increasingly popular vegetable in recent years--among producers, marketers, and consumers. Its long acclaimed nutritional and medicinal values are proving to be valid, more people are discovering its culinary splendor, and producers have found garlic to be a potentially highly profitable crop. This article will focus on production guidelines and tips, with some information on harvest, postharvest, and marketing.

Until recently, commercially grown garlic in California (which was synonymous to saying commercially grown garlic in the United States) was almost exclusively devoted to the "varieties" California Early, California Late and a small amount of Creole types. Except for a large, but relatively quiet, group of home gardeners and small scale radical garlic farmers, the rest of us were not exposed to and thus unaware of the almost innumerable types of garlic that exist. Experts and other garlic aficionados debate the correct scientific classification of all of these types, but for the purposes of keeping this article simple and, hopefully, useful, the generally agreed upon broad classification types and examples of each will be given.

Two main types, or subspecies, of garlic are ophioscorodon and sativum, which can also be called "hardneck garlic" and "soft neck garlic," or "bolting" and "non-bolting garlic." The ophioscorodon types are also sometimes referred to as "ophio" or "stick" garlic. The main difference between these two subspecies is that one almost always produces a seedstalk, the top of which will bear small aerial bulbils--not true seed--while the other rarely produces a seedstalk. The former (hardneck garlic) commonly, but with notable exceptions, have smaller bulbs with fewer, more uniform size, and more organized arrangement of cloves. The latter (softneck garlic), in contrast, commonly has larger bulbs, more numerous cloves in a more random arrangement and of more variable size. Flavors cannot be generalized, and their uniqueness and degrees of differences will depend on the discerning capabilities of the individual who is tasting. Examples of "ophio" types include Rocambole, Chinese, and many Creolian strains. Examples of softneck, or non-bolting types include California Early, California Late, Silverskin, and numerous strains collected from the former USSR republics.

Garlic originated in Central Asia, probably from the wild species, Allium longiscuspis, and does not occur in the wild as a species itself. While recent research has enabled sexual propagation of garlic, all of the garlic commonly grown is propagated vegetatively, and all of the current variation in garlic probably occurred through natural mutation. Because this variability is great, we conclude that garlic has the capability to mutate relatively easily; or, in other words, given time can adapt to new environments and appear to be different from the garlic introduced to an area.

Elephant garlic is not a true garlic, but rather a member of the leek family, Allium ampeloprasum. The combinations of the sulfur compounds, various allyl sulfides, that define the unique flavors of the numerous Alliums, is different in garlic and "Elephant garlic." The production guidelines and processes are very similar for garlic and "Elephant garlic," however, thus the following information can be considered equally applicable.

July, the date of this newsletter, is harvest time for garlic. It is also time for pre-planting time preparation, since ideal planting dates are September to continued

November, depending on the area. Primary pre-planting considerations are seed selection or purchase, and site selection and preparation. Seed availability has, and continues to be, a major obstacle for those who want to enter or stay in the garlic business. Seed quality is critical to successful production, yet few sources of quality seed, especially the more specialty varieties, exist. The California Department of Food and Agriculture (CDFA) conducts a certification program to assure freedom from nematode and white rot disease, two pathogens that can both destroy a crop as well as remain in the soil indefinitely, once introduced. CDFA publishes a list annually of the certified seed garlic growers; a number of nurseries and catalog order/supply companies also stock some seed garlic in the fall; Filaree Farm in Okanogan, Washington, has a large collection of "specialty" garlic varieties/strains; other farms scattered throughout the U.S. emphasize garlic and small farm interests. If you plan to save your own garlic for seed, or acquire it from your neighbor, special precaution is in order: make certain it is free from nematode, white rot, and any other serious diseases or insects (e.g. mites); save the best bulbs for seed; make certain it has or will meet the "chilling" requirement of garlic (important especially for central valley and desert regions).

Five planting considerations or recommendations are, as follows:

Earlier planting means higher yield potential. September to November planting is optimum. Early spring planting is OK, but small bulbs will result.

The size of bulbs harvested is directly related to the size of cloves planted and the spacing of the plants.

If you are buying seed, learn the cultural history of the garlic and the field in which it was grown; if saving your own seed, save the largest, best bulbs and cloves.

Plant immediately after "cracking" (dividing the bulbs into individual cloves). Individual cloves do not keep long, due to disease susceptibility and desiccation.

Cover the top of each clove with 1/2 to 2 inches of soil, depending on winter temperatures (colder winter requires deeper planting).

Five cultural practice considerations or recommendations are as follows:

Weeds are frequently the worst problem; garlic is a poor competitor; the crop is in the ground a long time. Avoid, prevent and control them.

Garlic is a moderate user of nitrogen; it may or may not require phosphorus, depending on the soil and previous management. It rarely responds to potassium fertilizer and rarely requires micronutrients. A good compost and/or organic matter management program will satisfy most garlic nutrition needs.

Up to half of the nitrogen needs should be available at planting or early in the season; another major need will occur in late winter, after rain caused leaching, and when the garlic begins its strong re-growth. No nitrogen should be applied during the last 60 days before harvest; the garlic should run out of nitrogen late in the season.

Garlic can grow in a wide range of soil textures and soil pH. Fertilization, irrigation, and harvest practices may be different for each combination of situations.

Diseases and insects to watch for include Fusarium basal rot, purple blotch, white rot, stem and bulb nematode, mites, and cutworms.

Harvest and postharvest considerations and recommendations include the following:

Maximum yield and optimum bulb quality for fresh market use are generally contradictory. Thus, compromise decisions must be made.

Begin harvest process--i.e., stop irrigation--when all cloves in a bulb show development, and a minimum of three to five outer wrapper leaves remain.

Dry the bulbs on top of the ground for several days, shading them with leaves from other plants, if possible. If braiding, do so while the tops still have moisture and are flexible, or least not so dry that the tops cannot be re-wet before braiding.

The longer the tops stay on, the longer the storage life will be. Air movement is essential to cure the bulbs and carry away moisture.

Store garlic in as cool and drya place as possible. Relative humidity must be below 70 percent to prevent mold. The lower the temperature, the longer the storage life.

Some marketing considerations include:

Green garlic (immature, pre-bulbing) is increasing in popularity. Small cloves, dense plant population, and thinning can be sources of green garlic harvests.

The seed stalks of Elephant garlic and stick/hardneck garlic can be promoted for use in stir fry recipes, appearing like asparagus, but with the great, unique garlic flavor.

The umbels of Elephant garlic, and some garlic, make attractive flower arrangements; bunches of umbels, harvested just before they begin to open, also have market and culinary appeal.

Value added products, in addition to braids, include peeled cloves in water, and a myriad of pureed garlic products.