Lettuce growers in central California experienced unseasonably high temperatures and crop disease that caused severe losses to iceberg and romaine varieties.
David Anderson, AgriLife Extension economist, Bryan-College Station, said the shortage is another instance of the nation’s food supply chain being disrupted.
Anderson said lettuce is one product in a long list of perishable food items that are produced to serve a “just-in-time inventory” for retail grocers, restaurants and ultimately consumers.
“Consumers have dealt with shortages related to COVID-19 disruptions most recently, but it looks like this is weather- and disease-related losses that resulted in supply issues,” he said. “We grow accustomed to seeing lettuce at the grocery store year-round, but a lot of folks don’t know we rely on producers all around the country and beyond to serve that year-round availability.”
Lettuce is a cool-season crop and performs best at 60-65 degrees. The crop requires temperatures stay consistently below 80 degrees, accompanied by cool night temperatures.
Anderson said Texas and the rest of the U.S. rely on growers in specific microclimates domestically, but also in Canada, Mexico and other parts of the world, to produce certain products like lettuce and spinach to meet year-round demand. The heatwave in California accompanied by leaf spot disrupted the harvest that growers’ in Salinas provide to meet demand now.
“In a couple of weeks it’ll be another areas turn to meet that demand, and so on, but it just shows how delicate the system can be if there is an issue in the supply chain,” he said.
Fresh produce takes time and timing
Juan Anciso, Ph.D., AgriLife Extension horticulturist, Weslaco, said Texas producers grow very little lettuce aside from niche-market growers who supply restaurants, specialty grocers and directly to consumers. But the region is part of the national supply chain for cool season produce.
Growers in the Rio Grande Valley, for instance produce thousands of acres of cool-season produce – mostly onions, leafy greens like spinach and kale, and carrots.
The planting window is critical for those cool season crops because of the time they take to mature, he said.
Onions take 160-170 days from seed to harvest. Cabbage takes 90-110 days, and carrots take 90-plus days for fresh market and 150-180 days for fields destined for processing.
“California is the breadbasket of America when it comes to many varieties of produce, including various kinds of lettuce,” he said. “The growing season moves north and south as seasonal temperatures dictate the crop, planting time and harvest.”
Anciso said these crops are also very dependent on timing because they are only marketable for a week or two once harvested.
“These are all extremely perishable foods,” he said. “They are grown, harvested and go directly to the stores, so timing the logistics of that is critical to supplying demand. We expect to see a head of lettuce when we go into a grocery store and take the process for granted until it’s not there.”