Onion family essential for cooking and good health

By Kathy Hatfield
Gardening Columnist

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Most of us are familiar with the vampire-dispelling properties of garlic, but there are other lesser-known medicinal properties of the onion family.

People have used onions to treat diabetes, insomnia, rheumatism, pneumonia, high cholesterol, tumors and high blood pressure. Current health food cookbooks include onions for their antioxidant properties and their heart-healthy sulfur compounds. Onions are a good source of iron, calcium, potassium and vitamin A.

Some of the health benefits of onions have been known for quite some time. Gen. Ulysses S. Grant sent a memo to the War Department during the Civil War saying he would not move his troops without onions; onion juice was an essential antiseptic for cleaning gunshot wounds.

The very same compounds that give onions and their relatives their healthy appeal are those responsible for their bite. Sulfur compounds in onion cells give them their characteristic odor and flavor. Cutting an onion releases the irritating compounds, but cooking destroys these compounds and some of the flavor as well. These same sulfur compounds are also antibacterial and antifungal, so that stronger onions with more of these chemicals are generally better keepers.

The onion family includes not only the many familiar varieties of garden onions, but also garlic, shallots, leeks, chives, Egyptian walking onions, Japanese bunching onions and rocambole, also called sand leek or serpent garlic.

Planting

Most members of the onion family prefer well-drained, fertile soil, amended with compost or well-rotted manure. Because onions grow slowly, it's important to keep the area free of weeds as they develop. Their shallow root systems mean they need regular watering. Competition for water and nutrients in a weedy onion patch will result in small onion bulbs.

Their beneficial relationship with mycorrhizal fungi in the soil helps onions extract the nutrients they need from the soil. If you use chemical fertilizers, you risk destroying these fungi and your onion crop will likely suffer. Onions are usually not plagued with disease or pest problems, but nonchemical controls will usually take care of any problems.

It's a bit late to start onions from seed if you want good-sized onions this year. But a convenient and reliable way to grow onions is to plant sets, or small onion bulbs. The most dependable sets are marble-sized, about 1/2 inch in diameter. Choose those that are quite firm, discarding any soft ones. Push the onion bulbs into the soil with the pointed end up and about 4 to 5 inches apart so that they have room to fully develop.

Shallots have a delicate flavor and are relatively expensive, but surprisingly easy to grow. Most people are familiar with the French shallot, a teardrop-shaped bulb with a pinkish skin. The Dutch shallots are larger, yellow-skinned, and have a stronger flavor. A third type is the frog-legged shallot; most experienced cooks claim that these have the best flavor, but they are also the most difficult to grow and less prolific than the other two. Both the French and the Dutch shallot store well when placed in a paper bag in a cool, dark place. Though shallots prefer a drier, leaner soil than bulbing onions, they must be kept weed free for a good harvest.

Leeks are a wonderful addition to soups when combined with potatoes and are a key ingredient in the French potato and leek soup called vichyssoise. The blue-green varieties tend to be a bit hardier than the standard green types. As with onions, leek seeds should be started very early in the spring. When transplanting them, trimming both the leaves and the roots may help to reduce transplanting shock. If you plant the leeks in a trench and fill in the trench as they grow, you will have tender, white leeks.

Chives and garlic chives will grow easily from seed or from dividing a clump. If you grow them from seed, it may take two to three months until they are large enough to harvest for kitchen use. As the chives flower in the spring, pick the flowers, or the chives may die back and go dormant.

Japanese bunching onions and Egyptian onions can be grown as perennials. Both of these are most easily started from clump divisions. If started in the fall, they should be heavily mulched before the ground freezes. Scallions are often substituted for Japanese bunching onions, which are popular in Asian cuisine, but the flavor is not quite the same.

Egyptian or tree onions are some of the earliest vegetables to awaken in the spring and have few pest or disease problems. The parent plant sends up aerial bulblets that resemble a Dr. Seuss-like tree. These can be eaten or used to propagate the plant. If you don't harvest them, the bulblet cluster will bend down and root in the soil, hence its other common name, walking onion.

E-mail Kathy Hatfield with your gardening questions at ocwildflowers@frii.com.