Organic lettuce is grown without the use of manmade pesticides, fertilizers, or herbicides. Any kind of lettuce qualifies, including head lettuce and leaf lettuce, as long as it is grown in soil that is free of chemical products and none are added. It also can’t be preserved or treated after harvest with anything that does not occur in nature. Stringent controls ensure that commercial growers meet the necessary requirements in order to label their produce as organic.
Many people choose to grow organic lettuce in their home gardens, where it is relatively easy to control additions to the plants and soil. The same methods will work at home or in commercial operations; the difference between the two is the scale of the operation. Soil is fertilized with aged compost that contains only organic materials, with worm castings from carefully fed worms, or with other organic fertilizers. For best results the soil should not have had any man-made products added to it for three or more years, which in some cases is a requirement for organic certification.
Pest control can be more difficult in some situations, as lettuce is vulnerable to different kinds of insect damage, including attacks by cabbage loopers, cutworms, aphids, and leaf hoppers. Since no pesticides are used in the growing of organic lettuce, other means of controlling pests must be found. One method that can have good results is to use predatory insects against the harmful ones, in order to diminish their numbers to the point that they can’t do any serious harm. Adding tiny Trichogramma wasps is an effective means of control for many different kinds of caterpillars, and ladybugs work hard to diminish the aphid population.
Since the application of herbicides is forbidden, weeds are usually controlled by more labor-intensive methods. Tractors or tillers work the soil between rows in order to minimize the weed population, but a certain amount of weeds are inevitable. Growers invest a lot of time keeping the weeds under control until the organic lettuce is well established and can hold its own.
Commercial growers of organic lettuce and other produce must keep careful records that show what crops were grown on each piece of land and detail every step of the growing process. Typically they must also be able to show that the seed they used was organically produced, proving that chemicals were avoided from the start. Government agencies oversee the certification process, and only those who meet the requirements are allowed to sell their produce as certified organic lettuce. The exception to this rule is that in some places farmers who have very small farms and limited sales do not need to be certified to sell organic produce.