Complex sentence: These growers often market their produce under alternative labels, such as "naturally grown", "chemical free", and the like, although some contend that they use growing methods superior to those specified by the USDA organic program.
Split into simpler sentences: These growers often market their produce under alternative labels such as "naturally grown", "chemical free", and the like. Some farmers even contend that they use growing methods superior to those specified by the USDA organic program.