U.S. consumers sitting down to a salad in the winter months can thank farmers who, around Labor Day, prepared the ground and planted the seed necessary to grow it. In this case, we chronicled the progression of romaine lettuce grown near Yuma, Ariz. over a two-month period. Harvest crews should be entering the field in the next week or two to harvest lettuce that will be packed and shipped within a couple days of harvest.

Sun, soil and the Colorado River all combine this time of year to grow America's winter vegetable crops, which currently are carpeting the desert Southwest in a sea of green.

These lettuce fields are owned by John Boelts of Desert Premium Farms.