Leafy lettuce greens not only taste better when grown locally and in season, but they could also be safer, too. Much of the lettuce sold in winter is grown in California, where lettuce fields are irrigated with water from the Colorado River. According to the Environmental Protection Agency, Colorado River water is contaminated with low levels of perchlorate, a component of rocket fuel known to harm thyroid function, and that perchlorate can be taken up inside lettuce plants. Any lettuce but iceberg is packed with antioxidants, so get those now from a local farmer who can tell you about any potential contamination sources from his or her water supplies.
How to Grow Lettuce