Crop of the Week: Leaf and mixed lettuce

• Yuma County's produce is off to a start with the harvesting of a small acreage of leaf lettuce in the eastern part of the county. By mid-November, the season will be in full swing.

• Production of leaf lettuce in Yuma has increased over 20 percent from 1998. In 2010, Yuma producers grew more than 8,000 acres of leaf lettuce valued at over $120 million. Leaf lettuce is the third ranking crop grown in the county, based on gross farmgate receipts. Most of Yuma's leaf lettuce is shipped by refrigerated truck to markets throughout the U.S. and Canada.

• In the 1970s, salad became a national obsession as salad bars sprang up everywhere. Along with increased interest in salad came widening choices of ingredients and more variety in salad dressings. Tuned-in restaurants served salads and sandwiches bulging with alfalfa sprouts and avocados, perhaps the two ingredients most identified with salads at that time. The 1990s initiated in the decade of convenience, with the emergence of the grocery store “salad mix,” pre-cut, pre-washed greens for an easy mixed green salad.

• Lettuce is a close relative of sunflowers, artichoke, chicory, endive and sunflowers. In the United States, lettuce is the second most popular fresh vegetable.

• Leaf lettuce is a descendant of the weed Lactuca serriola (prickly lettuce), which probably originated in the region stretching from Asia Minor into modern day Iran. The wild form is quite bitter, a characteristic that may be attributed to its milky sap. This sap contains lactucarium, which is similar to opium in that it has narcotic qualities. But don't dive into the salad bar looking for a high. Our modern lettuce doesn't contain any significant levels of this component.

• Thanks to horticultural work from the Roman period to the present, we are now enjoying around 2,000 years of work in developing our modern improved types and varieties of leaf lettuce.

• Leaf lettuce forms loose rosettes of leaves that can range in color from medium to dark green and some have red-tipped leaves. Among the more popular leaf lettuces are oak leaf, frilly red leaf and crinkly green leaf.

• In general, leaf lettuce is more perishable than head lettuce. Choose bunches with crisp, evenly colored leaves with no sign of wilting or yellowing. As with all greens, leaf lettuce should be washed and either drained completely or blotted with a paper towel to remove any excess moisture before being refrigerated in a plastic bag. It will keep this way up to about three days.

• Leaf lettuce is nutrient rich, providing 5 to 6 times the amount of vitamin A and five to 10 times the vitamin A compared to iceberg. Butterhead types are also are good sources of foliate, which helps prevent birth defects and may decrease risk of heart disease.

• Leaf lettuce is fun to use as a wrap. Add grilled chicken and salsa for a healthy entrée.

Source: Kurt Nolte is an agriculture agent and Yuma County Cooperative Extension director. He can be reached at knolte@cals.arizona.edu or 726-3904.